OpenVPN

From DD-WRT Wiki

(Difference between revisions)
Jump to: navigation, search
Revision as of 14:52, 25 June 2008 (edit)
Simkiss (Talk | contribs)
m (Disabling NAT)
← Previous diff
Current revision (02:52, 22 January 2020) (edit) (undo)
Rocketboy235 (Talk | contribs)
m (Authentication with username and password)
 
(233 intermediate revisions not shown.)
Line 1: Line 1:
 +{{languages|OpenVPN}}
OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations, including road warrior access, home/office/campus telecommuting, WiFi security, secure branch office linking, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls. OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations, including road warrior access, home/office/campus telecommuting, WiFi security, secure branch office linking, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls.
-There are two methods how to get OpenVPN on your router:+=Support=
-* use firmware with OpenVPN client included (starting from 23b2 from 2005-11-21 there is separate firmware). (easy method)+Refer to OpenVPN documentation for details on all OpenVPN features:
-* install openvpn package to [[jffs]] partition+*[http://openvpn.net/index.php/open-source/faq OpenVPN FAQ]
 +*[https://community.openvpn.net/openvpn/wiki/RelatedProjects#Services OpenVPN Related Project Services]
-Before you begin, you'll need to obtain the OpenVPN client [http://openvpn.net/gui.html (with the GUI)] ([http://www.openvpn.se Windows], [http://www.tunnelblick.net/ Mac]) for your client computer (if you don't already have it).+=Getting OpenVPN=
 +Install the OpenVPN client on the computer: [https://openvpn.net/community-downloads/ Windows], [http://www.tunnelblick.net Mac]
 +Please note that it consists of one binary for both client and server connections, they are not separate packages.
 +=OpenVPN authentication=
 +You will have several possibilities to authenticate to an openvpn session. Some authentication methods are supported by the gui directly (should be preferred), others have to be set up in daemon mode. Which you will use depends on some things: how secure, easy to setup, easy to maintain
 +==Public Key Infrastructure (PKI) [Certificates]==
 +Pro-Linux article (German) about PKI security (13 Sep 2013): [http://www.pro-linux.de/news/1/20246/roeckx-aktueller-stand-der-kryptografie.html Current state of cryptography] [[https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=https%3A%2F%2Fwww.pro-linux.de%2Fnews%2F1%2F20246%2Froeckx-aktueller-stand-der-kryptografie.html English translation]]
-=WARNING=+Follow these [http://openvpn.net/howto.html#pki instructions] to create the required certificates and keys. But there is also a Webmin module for linux servers to create your PKI infrastructure (OpenVPN CA). You begin by creating a key and certificate pair for the certificate authority (CA) you are establishing. Then for the server and each client, you create a private key and certificate pair and sign the certificates using the CA's key. Afterwards, you should have the following files:
-[[Image:WRT-FIXED-SCREEN.jpg|thumb|Description]]+
 + ca.crt
 + ca.key
 + dh{n}.pem
 + server.crt
 + server.key
-WRT54G V1 (possibly others) will not boot (red light) using the scripts in the sections below. +and a private key and certificate pair for each client. For example, if you have two clients, you should have:
-[http://www.dd-wrt.com/phpBB2/viewtopic.php?p=59370&highlight=&sid=bf968dbabfc61fa3f3e8ac52be21473a/ Documented case.]+
-Your rc_startup is way longer then max size for one nvram variable, which is 1024 bytes.+ client1.crt
-Consider writing keys and other information to the filesystem outside of NVRAM.+ client1.key
 + client2.crt
 + client2.key
-*'''NEED TO BUILD AND USE JTAG TO RECOVER? Check out:'''+'''Note: The CA private key (ca.key) is only to sign the certificates. Keep it secure and do not copy to the server nor clients.'''
-*http://wiki.openwrt.org/OpenWrtDocs/Customizing/Hardware/JTAG_Cable+
 +OpenVPN certs must be generated with SHA auth: see [https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=312247 this thread]
-Note: +==Static Key==
--'''The scripts on section 3.3 "Server Mode with Certificates" were run in a WRT150N v1.1 without any problems.''' After seeing the warning I was hesitant to run any of the scripts but risked it anyways. The case above may be specific to the WRT54G V1. --[[User:Wrtman|Wrtman]] 10:02, 18 May 2008 (CEST).+This method is only usable for connecting '''one''' client to a server!<br>
--Also '''no problems with dd-wrt.v24_mega_generic.bin on wrt54gs v1.0''' with full server mode with certificates.--[[User:Mutrax|mutrax]] 21:42, 18 May 2008 (CEST) +
--Tested on Asus WL-500G Premium v1 without any issues.+
-[Please, add your own experience with different routers here.]+
-=Download OpenVPN=+On Linux you can create a pair of keys with:
 + openvpn --genkey --secret /home/"user"/static.key
-Before you begin, you'll need to obtain and install the OpenVPN client ([http://openvpn.net/gui.html with the GUI]) ([http://www.openvpn.se/ Windows], [http://www.tunnelblick.net/ Mac]) for your client computer.+For Windows, ensure openvpn is installed. To create a pair of keys go to:
 + Programs -> OpenVPN -> Generate a static openvpn key
-Please note that it consists of one binary for both client and server connections, so don't look for individually labeled client or server packages.+Finally, copy the content of the keys to the ddwrt GUI static key field.
-=Enable OpenVPN in the Router=+Also see: [http://openvpn.net/index.php/open-source/documentation/miscellaneous/78-static-key-mini-howto.html Static Key How-To] and [http://openmaniak.com/openvpn_static.php Create Static Keypair]
-In this section, it is assumed that you already have the VPN flavor of DD-WRT installed in your router.+
-==Client Mode==+=OpenVPN in DD-WRT=
-# Using the [[Web_Interface|Web Interface]], go to the "Administration" tab and the "Services" sub-tab.+Forum thread: [https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=318795 OpenVPN server setup guide]<br>
-# Enable the "Open VPN Client" If new options do not appear, Apply Settings.+
-# Fill in parameters (see below)+
-# Apply Settings+
 +This assumes DD-WRT with OpenVPN is installed on the router. OpenVPN is only available on units with at least 8mb flash (except the Broadcom VPN build). Instructions may vary based on version, as the following is for builds since 2011.
-===Regular Parameters===+The DD-WRT GUI Server and Client modes' defaults should suffice for most users.
-;192.168.1.1: IP address of the OpenVPN server you want to work with+# Using the [[Web_Interface|Web Interface]], go to the "Services" tab and then the "VPN" tab (for older versions of dd-wrt go to the "Administration" tab and then the "Services" sub-tab).
-;80: port which OpenVPN server listens on+# Enable ''OpenVPN Daemon'' or ''OpenVPN Client''. If further options do not appear, click '''Apply Settings'''.
-;Use LZO Compression: where to use or not compression on vpn traffic; must be the same value as on server+# Fill in needed parameters (see below). Everything else not mentioned here is taken care of automatically (e.g. firewall)
-;Tunnel protocol: what transport to use to transfer VPN traffic; default is ''udp'', but if routers/nat devices causes problems, choose ''tcp''; must be the same as on server+# Click '''Apply Settings'''.
-;Public Server Cert: Certificate of OpenVPN CA in ''pem'' form; only part between (and including) <tt>-----BEGIN CERTIFICATE-----</tt> and <tt>-----END CERTIFICATE-----</tt> is necessary; as it is stored in [[nvram]], everything else from that file should be removed to conserve space+
-;Public Client Cert: Client certificate issued by CA for this particular router; also only part between 'BEGIN' and 'END' is required+
-;Private Client Key: Key associated with certificate above; should be kept secret because anybody who knows this key can successfully authenticate as this client+
 +Set up OpenVPN client where only specific traffic is routed via the VPN tunnel: [https://charleswilkinson.co.uk/2016/05/14/selective-routing-using-ddwrt-and-openvpn/ Selective Routing Using DD-WRT & OpenVPN]
-===Custom Parameters===+==CLI settings==
-If you want to set custom parameters (e.g. encryption settings, verbosity, ...) for OpenVPN, you'll have to re-create the <tt>/tmp/openvpn/openvpn.conf</tt> file and restart OpenVPN.+===Scramble Patch by clayface===
 +These posts adds a patch to openvpn which introduces forms of scrambling to the packet payload of any OpenVPN connection.
 +To use it you need both sides patched, server and client, and you introduce a new scramble password phrase in server and client config files
-For more detailed information on Startup Commands, please read the [[Startup_Scripts|Startup Scripts]] wiki entry.+ “scramble password” – perform a simple xor operation the packet payload, using a string “password”, you choose password
-To do this, use the [[Web_Interface|Web Interface]], go to the "Administration" tab and the "Commands" sub-tab.+ “scramble reverse” – This simply reverses all the data in the packet. This is enough to get past the regular expression detection in both China and Iran.
-In the box, enter the configuration how you'd want it, and echo it into <tt>/tmp/openvpn/openvpn.conf</tt>.+ “scramble xorptrpos” – This performs a xor operation, utilising the current position in the packet payload.
-Example (add this in the edit box at the top):+ “scramble obfuscate password” – This method is more secure. It utilises the 3 types of scrambling mentioned above. “password” is a string you choose.
-<pre>+
-echo "dev tap+
-link-mtu 1492+
-remote <remote-ip>+
-resolv-retry infinite+
-ifconfig <local ip> <local netmask>+==GUI: Client Mode==
-client+===Fixed Parameters===
-ca /tmp/openvpn/ca.crt+There are default parameters that will always be written to the config file and which you '''cant''' change if you use GUI client mode:
-cert /tmp/openvpn/client.crt+
-key /tmp/openvpn/client.key+
-comp-lzo+
-persist-tun+
-persist-key+
-verb 3+
-cipher AES-256-CBC" > /tmp/openvpn/openvpn.conf+
-killall openvpn+ ca /tmp/openvpncl/ca.crt
-openvpn --config /tmp/openvpn/openvpn.conf</pre>+ cert /tmp/openvpncl/client.crt
 + key /tmp/openvpncl/client.key
 + management 127.0.0.1 16
 + management-log-cache 50
 + verb 4
 + mute 5
 + syslog
 + writepid /var/run/openvpncl.pid
 + client
 + resolv-retry infinite
 + nobind
 + persist-key
 + persist-tun
 + script-security 2
 + tls-client
 + fast-io
-Next, click the ''Save Startup'', et voila, it should now start openvpn using your custom configuration.+===Changeable Parameters===
 +DD-WRT default settings in {} <br>
 +OpenVPN config language in []
-''Note:'' In "v23 SP2 (09/13/06) vpn" I've found that the openvpn startup script can run after the above during startup, so I work around that by doing the echo to "/tmp/openvpn/myopenvpn.conf" and replacing the killall/openvpn commands with:+;Server IP/Name (e.g. 192.168.1.1): IP address/hostname of the OpenVPN server you want to connect to. [remote xxx]
 +;Port: port which OpenVPN server is listening on. {1194} [port xxx]
 +;Tunnel Device (TUN/TAP): The mode of tunneling. TUN: routing (layer 3), TAP: bridgeing (layer 2. can be used for routing, too, but its not very common). [dev-type tun/tap]
 +;Tunnel Protocoll (UDP/TCP): The subprotocol the connection will use on the connection. {udp} [proto udp/tcp]
 +;Encryption Cipher (None and Blowfish to AES512): The encryption algorithm that will be used for the tunnel. Blowfish "fastest" to AES512 "safest". {AES128} [cipher xxx]
 +;Hash Algorithm (None and MD4 to SHA512): The hash algorithm that will be used. MD4: fastest (maybe unsafe) to SHA512. {SHA256} [auth xxx]
 +;Advanced options: Leave defaults as is if you dont know what you are doing. {disabled} []
 +;TLS Cipher: What encryption algorithm OpenVPN should use for encrypting its control channel. {disabled} []
 +;LZO Compression: Enables compression over VPN. This might speedup the connection. Must be the same value as on server. {adaptive} [comp-lzo yes/no/adaptive/disabled]
 +;NAT: Enable network address translation on the client side of the connection. Enables the NAT-firewall to protect clients. {disabled}
 +;Bridge TAP to br0: Enable a transparent bridge across the tunnel to the local LAN. Works only in TAP mode with NAT disabled. {disabled}
 +;Local IP Address: In cases you will not get an ip from the server. Not very common. {empty)
 +;Subnet Mask: Subnet Mask for the IP Address.
 +;TUN MTU Setting: set the mtu of the tunnel {1500} [tun-mtu xxx]
 +;UDP Fragment across the tunnel: set mss-fix and fragmentaion accross the tunnel. {empty} [fragment xxx]
 +;UDP MSS-Fix: = value of Fragment. Only usen with udp. should be set on one side only. [mssfix]
 +;nsCertType verification: Checks to see if the remote server is using a valid type of certificate meant for OpenVPN connections. As this is a security feature of OpenVPN, it should be left enabled. {checked} []
 +;TLS Auth Key: The static key OpenVPN should use for generating HMAC send/receive keys. {disabled} []
 +;Additional Config: Any additional configurations you want to define for the VPN connection. {empty}
 +;Policy based Routing: allow only special clients to use the tunnel. Add IPs in the form 0.0.0.0/0 to force clients to use the tunnel as default gateway. One line per IP. {} []
 +;Public Server Cert: Certificate of OpenVPN CA (not the server's public cert) in ''pem'' form; only part between (and including) <tt>-----BEGIN CERTIFICATE-----</tt> and <tt>-----END CERTIFICATE-----</tt> is necessary; as it is stored in [[nvram]], everything else from that file should be removed to conserve space.
 +;CA Cert: CA certificate; also only part between 'BEGIN' and 'END' is required.
 +;Private Client Key: Key associated with certificate above; should be kept secret because anybody who knows this key can successfully authenticate as this client.
 +;DH PEM: Diffie Hellmann parameter.
 +;Static Key: used for p2p links. No pki needed.
-( sleep 20 ; killall openvpn ; openvpn --config /tmp/openvpn/myopenvpn.conf --route-up /tmp/openvpn/route-up.sh --down /tmp/openvpn/route-down.sh --daemon ) &+==GUI: Server Configuration==
 +This section describes how to configure an OpenVPN server that uses SSL certificates for client authentication, which is recommended. The method offers better security than using a static key and allows multiple clients to connect at the same time.
-You may need to tune the amount of sleep time. Use "ps" to verify that the "openvpn" process you want to be running is running.+===Fixed Parameters===
 +There are default parameters in the DD-WRT config file that cannot be changed using the GUI server mode:
 + dh /tmp/openvpn/dh.pem
 + ca /tmp/openvpn/ca.crt
 + cert /tmp/openvpn/cert.pem
 + key /tmp/openvpn/key.pem
 + keepalive 10 120
 + verb 4
 + mute 5
 + log-append /var/log/openvpn
 + writepid /var/run/openvpnd.pid
 + management 127.0.0.1 5002
 + management-log-cache 50
 + mtu-disc yes
 + topology subnet
 + client-config-dir /tmp/openvpn/ccd
 + script-security 2
 + ifconfig-pool-persist /tmp/openvpn/ip-pool 86400
 + fast-io
 + passtos
---[[User:Ripper42|Ripper42]] 19:42, 30 Sep 2006 (CEST)+===Customizable Parameters===
 +DD-WRT default settings in {} <br>
 +OpenVPN config language in []
 +;Start Type: use "System". "WAN Up" doesnt work. {}
 +;Config via (GUI/config file): GUI {}
 +;Server Mode (TUN/TAP): The mode of tunneling. TUN: routing (layer 3), TAP: bridging networks (layer 2). {} [dev-type tun/tap]
 +;DHCP-Proxy mode: Only in bridge mode. Let the clients use the network dhcp server not the openvpn dhcp. {} []
 +;Pool start Ip: 1st ip of the ip pool used (Only in bridge mode). []
 +;Pool end IP: Last ip of the ip pool used (Only in bridge mode). []
 +;Gateway: Default gateway to use (Only in bridge mode). []
 +;Network (e.g. 10.10.10.0): Network to use for the tunnel (Only in routing mode). []
 +;Netmask (e.g. 255.255.255.0): Netmask of the used network. []
 +;Block DHCP accross the tunnel: Dont allow DHCP requests across tunnel (Only in bridge mode).
 +;Port: port which OpenVPN server listens on. {1194} [port xxx]
 +;Tunnel Protocoll (UDP/TCP): The subprotocol the connection will use on the real used tcp connection. {udp} [proto udp/tcp]
 +;Encryption Cipher (None and Blowfish to AES512): The encryption algorithm that will be used for the tunnel. Blowfish: fastest to AES512 safest. {AES128} [cipher xxx]
 +;Hash Algorithm (None and MD4 to SHA512): The hash algorithm that will be used. MD4: fastest (maybe unsafe) to SHA512. {SHA256} [auth xxx]
 +;Advanced options: Leave defaults as is if you dont know what you are doing. {disabled}
 +;LZO Compression: Enables compression over VPN. This might speedup the connection. Must be the same value as on server. {yes} [comp-lzo yes/no/adaptive/disabled]
 +;Redirect default Gateway: Force the clients to use the tunnel as default gateway. {disabled} []
 +;Allow Client to Client: Allow clients to see each other. {disabled} [client-to-client]
 +;Allow duplicate cn: allow to use 1 client cert to use on multiple clients (security risc)
 +;TUN MTU Setting: set the mtu of the tunnel {1500} [tun-mtu xxx]
 +;MSS-Fix/Fragment across the tunnel: set mss-fix and fragmentaion accross the tunnel. {empty} [fragment xxx] [mssfix]
 +;TLS Cipher: What encryption algorithm OpenVPN should use for encrypting its control channel. {disabled} []
 +;TLS Auth Key: The static key OpenVPN should use for generating HMAC send/receive keys.
 +;Client connect script: . {empty} []
 +;Additional Config: Any additional configurations you want to define for the VPN connection. {empty}
 +;CA Cert: Certificate of OpenVPN CA in ''pem'' form (usually ca.crt); only part between (and including) <tt>-----BEGIN CERTIFICATE-----</tt> and <tt>-----END CERTIFICATE-----</tt> is necessary; as it is stored in [[nvram]], everything else from that file should be removed to conserve space.
 +;Public Server Cert: Server certificate issued by CA for this particular router (usually server.crt); also only part between 'BEGIN' and 'END' is required.
 +;Private Server Key: Key associated with certificate above (usually server.key); should be kept secret because anybody who knows this key can successfully authenticate client certificates.
 +;DH PEM: Diffie Hellman parameters generated for the OpenVPN server (usually dh1024.pem).
-''Note:'' In "v23 SP2" the /tmp/ directory exist a few seconds after booting. So the script cannot run+===Authentication with username and password===
-immediately during bootup. Also I added a cronjob to check the openvpn connection every 5 minutes.+Certificates are nice, but having usernames and passwords can complement certificates. You can use the following scripts below to check for usernames/passwords.
-Here is my startup Script thats work for me:+
-<pre>#!/bin/sh+Add this to the config on the server and set the right path for the script:
-sleep 20+ script-security 2
-echo "tls-client+ auth-user-pass-verify /path/to/your/script/verify.sh via-file
-dev tun+
-...+
-cert /tmp/openvpn/client.crt+
-key /tmp/openvpn/client.key" > /tmp/openvpn/myopenvpn.conf +
-sleep 20+
-killall openvpn+
-/usr/sbin/openvpn --config /tmp/openvpn/myopenvpn.conf --route-up /tmp/openvpn/route-up.sh --down /tmp/openvpn/route-down.sh --daemon+
-# install cronjob, which restart tunnel if not running, but dont install cronjob, if it is already active+The script-security line is to resolve the issue where an external program may not be called due to setting of --script-security level
-if test -s /tmp/cron.d/openvpn_check_status; then echo "" ;else echo '*/5 * * * * root if [ `ps | grep -c "openvp[n]"openvp[n].*myopen"` -ne 1 ] ; then logger OpenVpn restart;. /tmp/.rc_startup ; fi' >> /tmp/cron.d/openvpn_check_status+The auth-user-pass-verify line enables the OpenVPN server to check the passed username and password by calling the script verify.sh and passing the username and password in a tmp file.
-# restart cron daemon+
-stopservice cron && startservice cron+
-fi +
-</pre>+
---[[User:Thomas Eimers|notdefine]] 16:52, 26.02.2006 after 100 edits+Every client will need to have this in its config file to connect:
 + auth-user-pass
-After looking at some posts and WiKi, I have simplified the process of using openVPN as a client.+This tells OpenVPN client to ask the user for username and password or s/he will not be able to log in. You can also use "--auth-user-pass" (instead of the line in the config file) on the command line.
-First, I enabled the openVPN client via the web interface and entered the 3 certificates/keys that are requested. Once I saved that, I disabled openVPN. This got the 3 certs/keys into nvram. I then ran the following 3 nvram commands in the command window at the same time:+I have split up the functions into separate files compared to predecessors (See page history).
-<pre>+The verification done by the script may not work if OpenVPN is running in "daemon" mode (to be confirmed).
-nvram set openvpn_tls='+
------BEGIN OpenVPN Static key V1-----+
-...+
------END OpenVPN Static key V1-----+
-'+
-nvram set openvpn_cfg='+
-remote remote_server_ip_address+
-dev tun0+
-tun-mtu 1500+
-fragment 1300+
-mssfix+
-tls-client+
-ca /tmp/myvpn/ca.crt+
-cert /tmp/myvpn/client.crt+
-key /tmp/myvpn/client.key+
-ns-cert-type server+
-tls-auth /tmp/myvpn/tls.key+
-ping-restart 60+
-ping-timer-rem+
-persist-tun+
-persist-key+
-resolv-retry 86400+
-ping 10+
-comp-lzo+
-'+
-nvram commit+
-</pre>+
-I then set the startup script to:+
-<pre>+
-/usr/sbin/openvpn --mktun --dev tun0+
-ifconfig tun0 192.168.tunnel.2 netmask 255.255.255.252 promisc up+
-route add -net 192.168.rlan.0 netmask 255.255.255.0 gw 192.168.tunnel.1+
-sleep 20+
-mkdir /tmp/myvpn+
-nvram get openvpn_ca >/tmp/myvpn/ca.crt+
-nvram get openvpn_client >/tmp/myvpn/client.crt+
-nvram get openvpn_key >/tmp/myvpn/client.key+
-nvram get openvpn_tls >/tmp/myvpn/tls.key+
-nvram get openvpn_cfg >/tmp/myvpn/remote.ovpn+
-/usr/sbin/openvpn --daemon --config /tmp/myvpn/remote.ovpn+
-</pre>+
-and firewall to:+
-<pre>+
-iptables -I INPUT 2 -p udp --dport 1194 -j ACCEPT+
-iptables -I FORWARD -i br0 -o tun0 -j ACCEPT+
-iptables -I FORWARD -i tun0 -o br0 -j ACCEPT+
-</pre>+
-Explanations:<br>+
-openvpn_tls is set to your TLS key.<br>+
-remote_server_ip_address = IP address of remote openVPN running in server mode.<br>+
-192.168.tunnel.2 = 192.168.x.x address of the local openVPN tunnel. Must be different subnet from remote and local LANs.<br>+
-192.168.tunnel.1 = 192.168.x.x address of the remote end ofl openVPN tunnel. Must be different subnet from remote and local LANs.<br>+
-192.168.rlan.0 = IP address range of remote LAN<br>+
-sleep 20 = wait period to ensure /tmp has been created.+
-This disables the firewall and NAT on the VPN, uses TLS authentication, etc. Hope this helps some. It is easy to change nvram and was much easier for me to review than trying to put it all in startup scripts.+[Edit by Rocketboy235 Jan 21 2020]
 +The script below has been updated to make use of SHA1 checksum instead of MD5 since the last time I created it back in mid 2018. However, SHA1 has been cracked since early 2019 so hopefully dd-wrt will come packaged with a more secure/newer hash tool that can be used. Also added instructions on how to setup the scripts for OpenVPN login authentication.
-This is working on a Buffalo WHR-G54S running 2.3 SP2.+'''Instructions on how to use the below scripts'''
---[[User:PeteSL|Pete]] 14:29, 5 May 2007 (CEST)+Add both scripts to your router and make sure to do chmod +x for each file.
 +Then you can run Genhash.sh and pass the username and password arguments.
 +Example:
-===Disabling NAT===+./genhash.sh NameOfMyUser MyLovelyPassword
-To have OpenVPN pass traffic normally without address translation, you'll want to turn off masquerading on the tunnel interface as well as set a more permissive default for the firewall. Unfortunately, dd-wrt currently does not have an easy button to do this. Instead, use the startup script to replace the default route-up script with your own version. 
-To do this, use the [[Web_Interface|Web Interface]], go to the "Administration" tab and the "Commands" sub-tab, and add the following line to your [[Startup_Scripts|Startup Script]]:+This will generate a users file in /tmp and you can move it to whereever you like but you will need to update the Verify.sh script (line 14 ( begins with 'users=' )when you copy/paste this script) so that it points to that file when looking at the user list. For example, I place these scripts and my users file in /jffs/etc/openvpn/. Just note that if you save stuff in /tmp, you will lose them when the router reboots or loses power.
- ( while [ ! -f /tmp/openvpn/route-up.sh ]; do sleep 1; done; \+'''Verify.sh'''
- echo "iptables -t filter -I INPUT -i tun0 -j ACCEPT; iptables -t filter -I FORWARD -i tun0 -j ACCEPT" > /tmp/openvpn/route-up.sh ) &+
- +
- +
-----+
-==Server mode with Static Key==+ <nowiki>
 +#!/bin/sh
 +#verify.sh
 +#This script was made with via-file in mind
-''Note:'' with ''DD-WRT v23 SP1 Final (05/16/06) vpn'' this allows only 1 client connection!! [http://forum.bsr-clan.de/ftopic5111-0-asc-45.html]. See below for multiple connections.+PATH=/usr/bin:/bin
 +#Function used for generating SHA1 hash value of password multiple times
 +function hashround() {
 + local hash rest
 + read hash rest
 + printf '%s%s' "$hash" "$hash" | /usr/bin/sha1sum
 +}
-===Configuration===+#Location of the Approved Username/Password File
-# Create a static.key file on your computer+users="/location/of/the/file/for/users"
-Unix:+#Check to see if generated OpenVPN login file has any special characters
- openvpn --genkey --secret static.key+#Terminate script if special characters are used
 +if /bin/grep -q '[^-_a-zA-Z0-9]' "$1"
 +then
 + echo "Illegal characters found in username/password." >&2
 + exit 1
 +fi
-Windows:+#1st line is the username
 +username=`/usr/bin/awk 'NR==1' "$1"`
 +#2nd line is the password
 +password=`/usr/bin/awk 'NR==2' "$1"`
- Start > OpenVPN -> Generate a static OpenVPN key+#Generate SHA1 hash of given password and loop it 10 times before comparing with hash value in users file
- (Note: this might create a key.txt file, you will want to rename it to static.key)+hashpass=$(printf '%s%s' "$username" "$password" | /usr/bin/sha1sum \
- (Note2: It should show up in the OpenVPN\config folder)+ | hashround | hashround | hashround | hashround | hashround \
- (Note3: OpenVPN for windows can be downloaded at http://www.openvpn.se)+ | hashround | hashround | hashround | hashround | hashround \
 + | /usr/bin/cut -d' ' -f1)
 +
 +if /bin/grep -Fxq "$username:$hashpass" "$users"
 +then
 + echo "User Authenticated." >&2
 + exit 0
 +fi
-* Paste the command below into Administration > Commands > Commands text box and click '''"Save firewall"''' (replacing the "443" with the port you are going to use):+echo "Login credentials failed." >&2
 +exit 1
 + </nowiki>
- iptables -I INPUT 1 -p tcp --dport 443 -j ACCEPT+'''Genhash.sh'''
- Notes/References: [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude]'s [http://forum.bsr-clan.de/viewtopic.php?p=40508#40508 Post regarding the rc_firewall command]+ <nowiki>
- For More Information on startup scripts see [[Startup_Scripts]]+#!/bin/sh
-* Enter the code below in the commands field changing the "...INSERT YOUR OWN CONTENT HERE..." with the contents from the static.key file you created and Click '''"Save Startup"'''+#genhash.sh
 +#Generate Hash for username/password
 +#Case sensitive and only allows a certain set of characters to be used
- openvpn --mktun --dev tap0+function hashround() {
- brctl addif br0 tap0+ local hash rest
- ifconfig tap0 0.0.0.0 promisc up+ read hash rest
- echo "+ printf '%s%s' "$hash" "$hash" | /usr/bin/sha1sum
- -----BEGIN OpenVPN Static key V1-----+}
- ...INSERT YOUR OWN CONTENT HERE...+
- -----END OpenVPN Static key V1-----+
- " > /tmp/static.key+
- ln -s /usr/sbin/openvpn /tmp/myvpn+
- /tmp/myvpn --dev tap0 --secret /tmp/static.key --comp-lzo --port 443 --proto tcp-server --verb 3 --daemon+
-* Reboot your router. Login with ssh and check that "myvpn" is running (ps | grep vpn)+case "$1" in *[!-_a-zA-Z0-9]*) exit 1 ;; esac
-** You can also paste the "ps | grep vpn" command into the Administration > Commands box to see if it is running+case "$2" in *[!-_a-zA-Z0-9]*) exit 1 ;; esac
-''Note:'' I have had problems with TCP. My connection would frequently drop. Eventually, I seem to have solved the problems by switching my VPN to UDP. +hashpass=$(printf '%s%s' "$1" "$2" | /usr/bin/sha1sum \
-* See here: http://www.dd-wrt.com/phpBB2/viewtopic.php?p=54741+ | hashround | hashround | hashround | hashround | hashround \
 + | hashround | hashround | hashround | hashround | hashround \
 + | /usr/bin/cut -d' ' -f1)
 +
 +echo "Username: $1"
 +echo "Password: $2"
 +echo "Password (SHA1 Hashed): $hashpass"
-* Create an openvpn config file on your client computer using one of the following templates:+echo "User added to approved user file which is saved in /tmp/users"
- # Use the following for simple connections:+echo "$1:$hashpass" >> /tmp/users
- remote XXXX.dyndns.org+ </nowiki>
- port 443+
- dev tap+
- secret static.key+
- proto tcp-client+
- comp-lzo+
- +
- # Use the following to have your client computer send all traffic through your router+
- # (remote gateway)+
- remote XXXX.dyndns.org+
- port 443+
- dev tap+
- secret static.key+
- proto tcp-client+
- comp-lzo+
- route-gateway 192.168.1.1+
- redirect-gateway+
- +
- # Use the following if you have an office proxy:+
- remote XXXX.dyndns.org+
- http-proxy-retry+
- http-proxy my.office.proxy.server 8080+
- port 443+
- dev tap+
- secret static.key+
- proto tcp-client+
- comp-lzo+
- route-gateway 192.168.1.1+
- redirect-gateway+
- +
- Be sure to replace the above port with the port you are using.+
- Save it as a .ovpn file in the OpenVPN\config folder on your client computer+
- Reference: fgimenez's [http://forum.bsr-clan.de/viewtopic.php?p=40508#40508 post]+
- +
-* try to connect +
-** Windows: right click the open vpn icon in your system tray and click connect+
- +
- +
-That should do it. This has been tested on DD-WRT v23 SP1 Final vpn. +
- +
-If everything is working correctly you should receive an IP address from your router (if you have a running dhcp server) when you connect and that IP address will be in your internal LAN so now you just connect to your home PC the same way you would do it from inside your LAN.+
- +
-==Server Mode with Certificates==+
- +
-This section describes how to configure an OpenVPN server that uses SSL certificates for client authentication. The method offers better security than using a static key and allows multiple clients to connect at the same time.+
- +
- +
-===Public Key Infrastructure (PKI)===+
- +
-Follow these [http://openvpn.net/howto.html#pki instructions] to create the required certificates and keys. You begin by creating a key and certificate pair for the certificate authority (CA) you are establishing. Then for the server and each client, you create a private key and certificate pair and sign the certificates using the CA's key. Afterwards, you should have the following files:+
- +
- ca.crt+
- ca.key+
- dh{n}.pem+
- server.crt+
- server.key+
- +
-and a private key and certificate pair for each client. For example, if you have two clients, you should have:+
- +
- client1.crt+
- client1.key+
- client2.crt+
- client2.key+
- +
-Note that the CA private key, ca.key, is used only to sign the certificates. It should be kept securely and not be copied to the server or clients.+
- +
- +
-===Server Configuration===+
- +
-*'''Warning:''' This Script EXCEEDS NVRAM - will semi-brick you router - JTAG required to recover. '''See first section.'''+
- +
- +
-1. Install DD-WRT with VPN, v23 SP2 or later, on your router.+
- +
-2. Create a rc_startup script (temporarily prepare in a simple text editor, e.g. notepad)+
- +
- cd /tmp+
- openvpn --mktun --dev tap0+
- brctl addif br0 tap0+
- ifconfig tap0 0.0.0.0 promisc up+
- +
- echo "+
- # Tunnel options+
- mode server # Set OpenVPN major mode+
- proto udp # Setup the protocol (server)+
- port 1194 # TCP/UDP port number+
- dev tap0 # TUN/TAP virtual network device+
- keepalive 15 60 # Simplify the expression of --ping +
- daemon # Become a daemon after all initialization+
- verb 3 # Set output verbosity to n +
- comp-lzo # Use fast LZO compression +
- +
- # OpenVPN server mode options+
- client-to-client # tells OpenVPN to internally route client-to-client traffic +
- duplicate-cn # Allow multiple clients with the same common name+
- +
- # TLS Mode Options+
- tls-server # Enable TLS and assume server role during TLS handshake +
- ca ca.crt # Certificate authority (CA) file+
- dh dh1024.pem # File containing Diffie Hellman parameters +
- cert server.crt # Local peer's signed certificate+
- key server.key # Local peer's private key +
- " > openvpn.conf+
- +
- echo "+
- -----BEGIN CERTIFICATE-----+
- ...INSERT YOUR ca.crt HERE...+
- -----END CERTIFICATE-----+
- " > ca.crt+
- echo "+
- -----BEGIN RSA PRIVATE KEY-----+
- ...INSERT YOUR server.key HERE...+
- -----END RSA PRIVATE KEY-----+
- " > server.key+
- chmod 600 server.key+
- echo "+
- -----BEGIN CERTIFICATE-----+
- ...INSERT YOUR server.crt HERE...+
- -----END CERTIFICATE-----+
- " > server.crt+
- echo "+
- -----BEGIN DH PARAMETERS-----+
- ...INSERT YOUR dh1024.pem HERE...+
- -----END DH PARAMETERS-----+
- " > dh1024.pem+
- +
- sleep 5+
- openvpn --config openvpn.conf --daemon+
- +
-Replace "...INSERT YOUR [FILE] HERE..." with the appropriate contents of the files you created earlier. Open these files in a simple text editor and paste contents between the BEGIN and END statements into this script.+
- +
-Notes:+
-* This script bridges the VPN with the LAN, so no routing is required so that clients can communicate with systems and devices on the LAN.+
-* The server is configured to use UDP packets since TCP over TCP can lead to poor performance. If you need to use TCP instead of UDP, specify ''tcp-server'' as the protocol.+
-* You might need to change the last line of the script to (strongly recommended):+
- +
- ln -s /usr/sbin/openvpn /tmp/myvpn+
- /tmp/myvpn --config openvpn.conf +
- +
-The reason is that with the original command, [http://www.dd-wrt.com/phpBB2/viewtopic.php?t=5053 openvpn might start but mysteriously not stay open].+
- +
-3. Add the following line to your rc_firewall script (create a new file in simple text editor that will temporarily hold your rc_firewall script):+
- +
- /usr/sbin/iptables -I INPUT -p udp --dport 1194 -j ACCEPT+
- +
-This command allows connections to the OpenVPN server.+
- +
-4. Use the [http://www.dd-wrt.com/wiki/index.php?title=Startup_Scripts#Web_Interface_Method web interface method] to store the rc_startup and rc_firewall scripts on the router.+
- +
-5. Enable NTP and uncheck ''Use Local Time'' in the router setup. Then reboot your router.+
- +
-''Note:'' As of V24-RC4 ''Use Local Time'' does not exist. Instead set ''Time Zone'' to "UTC" and ''Summer Time(DST)'' to "none".+
- +
-6. Login via ssh or telnet and execute the command+
- +
- ps | grep openvpn+
- +
-to verify that the OpenVPN process is running.+
===Client Configuration=== ===Client Configuration===
- 
1) Copy the CA certificate and a private key and certificate pair to the client. 1) Copy the CA certificate and a private key and certificate pair to the client.
Line 427: Line 321:
Notes: Notes:
* If you need to use TCP instead of UDP, set the protocol to ''tcp-client''. Clients must use the same protocol that the server does. * If you need to use TCP instead of UDP, set the protocol to ''tcp-client''. Clients must use the same protocol that the server does.
-* Mac OS X users need to add the line+* Client config also need match these server parameters: dev (tun/tap), cipher, auth, comp-lzo, tun-mtu.
 +* Mac OS X users and Linux users using TAP need to add the line
up "./vpn-up.sh" up "./vpn-up.sh"
-to the configuration file and create a script file ''vpn-up.sh'' in the same directory as the configuration file with the following contents:+to the configuration file and create a script file ''vpn-up.sh'' in the same directory as the configuration file with the following contents.
 + 
 +On Mac:
#!/bin/bash #!/bin/bash
 + sleep 2
ipconfig set $1 DHCP ipconfig set $1 DHCP
-This script configures the TAP interface to request an IP address using DHCP. Make sure to make the script executable with 'chmod 755 vpn-up.sh'+On Linux:
 + 
 + #!/bin/bash
 + sleep 2
 + dhclient $1 &
 + 
 +This script configures the TAP interface to request an IP address using DHCP. Make sure to make the script executable with 'chmod 755 vpn-up.sh'.
3) Use the configuration file you just created with whatever OpenVPN client software you're using to establish a connection to your router. 3) Use the configuration file you just created with whatever OpenVPN client software you're using to establish a connection to your router.
Line 442: Line 346:
If everything works, you will be connected to your internal LAN. If your router is running a DHCP server, the TAP interface will be assigned an IP address on your internal LAN. At this point, you just connect to your home PC the same way you would do it from inside your LAN. If everything works, you will be connected to your internal LAN. If your router is running a DHCP server, the TAP interface will be assigned an IP address on your internal LAN. At this point, you just connect to your home PC the same way you would do it from inside your LAN.
-=Installing into jffs partition=+==Daemon Mode/Config File==
 +[http://www.dd-wrt.com/wiki/index.php/OpenVPN-Site-to-Site-Bridged Bridge 2 Networks]<br>
 +[http://www.dd-wrt.com/wiki/index.php/OpenVPN_-_Site-to-Site_routed_VPN_between_two_routers Route 2 Networks]
-old method only recommended for non-vpn firmware+=Troubleshooting=
 +==FAQ==
 +===MTU===
 +One verycommon problem is the wrong setting of the mtu/fragment/mss-fix values. Ethernet's max frame size is 1500. In most cases where the Router is the gateway and the vpn connects to the outside world the values must be changed. WAN connections in general will have a lower frame size so the default setting will result in a dropping connection. mtu/fragment must be set the same on both sides!
-'''This no longer works with the latest firmware version, please download the new VPN inclusive version. !!However, with at least some new firmware versions (I'm using V23SP1 6/5/06 VOIP), the hurdle can be overcome with some extra effort ... details are provided below in the Troubleshooting section... 19:22, 30 Jun 2006 (CEST)!! '''+On tcp connections only mtu can be set. Try setting the mtu to 1300 and see if it works.
 +
 +On udp connections enable mss-fix on '''one''' side of the link. Lower the fragemt size to 1300 and try if its working.
 +
 +In both cases when the link is working u can try to raise the values again to the maximum which will be working.
-===Prerequisites===+==Logs==
- ''You should already have:''+logs are written to syslog and can be seen in the GUI: Status -> OpenVPN (not in daemon and script mode)
- -a Linksys WRT54G/GS product+
- -DD-WRT installed as the firmware+
- -[[Telnet/SSH and the Command Line#SCP|SCP]] or some other way to copy files to and from your desktop setup+
- -some knowledge of using [[ipkg]] to install packages+
- -[[jffs]] already configured if you don't want to install to ram<br>+
- ''If you are running Windows on your desktop:''+
- -[http://www.textpad.com/ TextPad] or [http://www.gena01.com/win32pad/win32pad_1_5_7.exe Win32Pad]<br> (or other *nix friendly text editor. DO NOT USE NOTEPAD)+
-====Install the OpenVPN ipkg package==== 
- -Find the '''openvpn''' package in the THIS LINK DOES NOT WORK ANY MORE [http://tracker.openwrt.org/ OpenWRT Package Tracker].<br> You will need the URI of package to install it.<br> 
- -telnet or ssh shell into the router 
- -run the command ipkg -d <dest_name> install <URI of package><br> 
- <dest_name> should be ''root'' to install to /jffs 
- <dest_name> should be ''ram'' to install to /tmp 
- *Remember, /tmp is deleted on router reboot* 
- Ex: ''ipkg -d root install http://nthill.free.fr/openwrt/ipkg/experimental/20050420/openvpn-static_2.0-1_mipsel.ipk'' 
- 
-'''EDIT: Can't find the right package?''' Yeah, neither can anyone else. Don't bother. The best strategy is to download and flash the distro with the built-in VPN and copy the binary off of that then re-flash with another distro and copy the binary to the jffs partition. The packages on the openWRT tracker don't seem to work for v23 on WRT54Gv3 ("Bus Error"). The version originally linked above and the version in the VPN firmware are statically compiled. I had to do it this way because the nvram startup script only ran the first command in the variable and I needed the VPN to survive a WRT reboot. Not enough room for jffs on all but the mini distro... so no shell scripts for me! YMMV. Note to the powers that be: How about posting this stuff with the mini firmware so we don't have to do it this way????? 
- 
-====Create the openvpn config file==== 
- -Using your method of choice, copy the file /<dest_name>/etc/openvpn/office.conf<br> to your desktop machine 
- -Using a *nix friendly text editor, edit office.conf (the config file in my setup).<br>See http://openvpn.net for more informations and examples. 
- 
-19:16, 30 Jun 2006 (CEST) [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude] 
- 
-- NOTE : openvpn is highly configurable. Distinct from the original writer of this portion of the wiki, I setup my configuration files much more along the lines of the earlier section in this Wiki on configuring the OpenVPN server with certificates in bridging mode. Certificates provide a more robust dynamic configuration scheme, but take a little bit more time up-front to generate (but the http://www.openvpn.net site has an excellent, easy-to-follow guide on how to generate them). Bridging mode is very convenient in that the remote VPN client effectively appears to be part of the remote(server) LAN, plus much less routing configuration (i.e. use of ifconfig, route etc.) is required on either the OpenVPN server or the OpenVPN client. 
- 
-19:16, 30 Jun 2006 (CEST) [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude] 
- 
-?? BUT HOW WOULD YOU SET THIS UP (with Certificates and Bridging) IF YOU HAVE MULTIPLE CLIENTS? 
- 
-<pre> 
-############################################################################## 
-# this is a sample configuration file for openvpn 
-# it should be changed to contain your values and 
-# placed in /jffs/etc/openvpn 
-# 
-remote servername.domain.com 
-rport 5000 
-dev tap 
-ifconfig 10.0.1.2 255.255.255.252 
-secret /jffs/etc/openvpn/key.txt 
-ping 10 
-ping-restart 60 
-ping-timer-rem 
-persist-tun 
-persist-key 
-resolv-retry 86400 
-verb 1 
-mute 10 
-route-up "route add -net 192.168.1.0 netmask 255.255.255.0 gw 10.0.1.1" 
-# 
-############################################################################## 
-</pre> 
- 
-This is the OpenVPN config file of the other side (a Linux server or another WRT54G/GS) 
-<pre> 
-############################################################################## 
-# 
-dev tap 
-secret /etc/openvpn/key.txt 
-persist-key 
-persist-tun 
-ifconfig 10.0.1.1 255.255.255.252 
-ping-restart 60 
-ping 10 
-verb 5 
-mute 10 
-lport 5000 
-route-up "route add -net 192.168.2.0/24 gw 10.0.1.2" 
-# 
-############################################################################### 
-</pre> 
- 
-===Usage & Troubleshooting=== 
-====Launching the Client==== 
- -cd to the install folder (/<dest_name>/usr/sbin) 
- -run ''./openvpn --config ./../../etc/openvpn/office.conf'' --log openvpn.log 
- 
-See openvpn.log for debugging 
- 
-===Load on Router Startup=== 
--Using a *nix friendly text editor, create openvpn.startup as: 
-<pre> 
-#!/bin/sh 
-killall -q openvpn 
-/jffs/usr/sbin/openvpn --config /jffs/etc/openvpn/office.conf 
-</pre> 
- 
--Follow the instructions in [[Startup Scripts#Shell Script Method]] to make your script load on startup. 
- 
-==Additional notes for improved JFFS installation and security with public hotspots== 
- 
-19:10, 30 Jun 2006 (CEST) [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude] 
- 
-i) The instructions above confine the OpenVPN server configuration entirely into a rc_startup script. This is elegant when OpenVPN is installed in RAM, since there's no convenient place to put a configuration file for OpenVPN (RAM contents are not persistent). However, if the user instead installs OpenVPN into persistent storage, i.e. the jffs partition, then instead of configuring OpenVPN on the command line, a config file can be used. There are several advantages to doing this; not only is RAM usage minimized (key files don't need to be copied to rc_startup, command line options get transferred to the config file, etc.), but the config file allows the description of more complicated openvpn server configurations. 
- 
-ii) One interesting capability of the OpenVPN tunnel is to optionally allow the client to pass ''all'' traffic through the VPN tunnel when connected. For example, when you are using an unsecure WiFi hotspot, you might want to ensure that eavesdroppers are not able to monitor your WiFi traffic. One way to do this is to route all your WiFi traffic through the encrypted VPN tunnel, using the "redirect-gateway" option on the server or the client. When configured on the server, all clients will reroute all their traffic through the VPN. The "redirect-gateway" option requires pushing two pieces of information from the server to the client, the remote gateway and DNS IP addresses. 
- 
-Here are my example rc_startup, server, and client config files. Note that I installed OpenVPN in /jffs/tmp and copied the PKI files, ca.crt, server.crt, server.key, dh1024.pem, and the server config file, server.conf, there. 
- 
-rc_startup: 
-cd /jffs/tmp 
-./openvpn --mktun --dev tap0 
-brctl addif br0 tap0 
-ifconfig tap0 0.0.0.0 promisc up 
-sleep 5 
- 
-;I had to install this library, since my ddwrt distro didnt have it 
-;See Troubleshooting section at the bottom of this wiki for JFFS installations 
-export LD_PRELOAD=/jffs/sbin/libuClibc-0.9.28.so 
- 
-./openvpn --config server.conf --daemon 
-</pre> 
- 
-Note: With V23 SP2, I did not need the LD_PRELOAD statement. I did have to create a link: 
- 
- ln -s /usr/sbin/openvpn /jffs/tmp/myvpn 
- 
-and change the last part of the code above to: 
- 
- sleep 5 
- ./myvpn --config server.conf --daemon 
- 
-server.conf: 
-<pre>mode server 
-tls-server 
-port 1194 
-proto tcp-server 
-dev tap0 
- 
-ca ca.crt 
-cert server.crt 
-key server.key 
-dh dh1024.pem 
- 
-#These IP addresses need to be changed to be *your* ddwrt LAN addresses ... 
-push "route-gateway 192.168.3.1" 
-push "dhcp-option DNS 192.168.3.1" 
- 
-client-to-client 
- 
-keepalive 15 60 
- 
-comp-lzo 
-persist-key 
-persist-tun 
-status openvpn-status.log 
-verb 3 
-</pre> 
- 
-client.conf: 
-<pre>tls-client 
-dev tap 
-proto tcp-client 
-port 1194 
-resolv-retry infinite 
-nobind 
-persist-key 
-persist-tun 
-remote XXXX.dyndns.org 1194 
- 
-ca ca.crt 
-cert client.crt 
-key client.key 
-ns-cert-type server 
- 
-comp-lzo 
-verb 3 
- 
-#Pull info from server, viz. server-side LAN IP's for gateway and DNS 
-pull 
-# Uncomment the following to send all traffic through VPN 
-redirect-gateway 
-</pre> 
- 
-19:10, 30 Jun 2006 (CEST)  
- 
-76472429234521330421186 
- 
-=Troubleshooting= 
===Correct time=== ===Correct time===
OpenVPN requires client and server to have more or less synchronized time. Therefore make sure that router has correct time. To check it use command <tt>date</tt> and if you get info about year 1970, you should enable [[NTP client]]. Also, ntp server has to be outside of your VPN as time should be corrected before VPN is established. If you have [[syslog]] enabled (to local server, or the server outside your VPN), errors like <tt>TLS Error: Unroutable control packet received from ''server_ip'':1194</tt> may indicate this problem. (This error message may appear if your certificates are not valid or have expired, too.) OpenVPN requires client and server to have more or less synchronized time. Therefore make sure that router has correct time. To check it use command <tt>date</tt> and if you get info about year 1970, you should enable [[NTP client]]. Also, ntp server has to be outside of your VPN as time should be corrected before VPN is established. If you have [[syslog]] enabled (to local server, or the server outside your VPN), errors like <tt>TLS Error: Unroutable control packet received from ''server_ip'':1194</tt> may indicate this problem. (This error message may appear if your certificates are not valid or have expired, too.)
 +If you get an error message saying that your certificate is not yet valid, set the dd-wrt clock to UTC time (in the first configuration page).
-===openvpn does not start, gives error message " ... can't resolve symbol 'fopen64' "===+To set the time manually connect via telnet or ssh and issue the following command at the prompt:<br>
 +'''date MMDDHHMMYYYY'''
-19:13, 30 Jun 2006 (CEST) [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude]+===Connecting to DD-WRT OpenVPN Server via Mac Client===
 +Currently, there are two OpenVPN clients for OS X
 +* [https://tunnelblick.net Tunnelblick]
 +* [https://www.sparklabs.com/viscosity/ Viscosity]
-I have V23SP1 5/6/06 VOIP, extracted the openvpn executable from V23SP1 5/6/06 VPN and copied it to my jffs partition as outlined above, and set everything up as outlined above, except that I setup my own configuration files, of course. Then I got the above error message.+Viscosity has a more user friendly GUI but is a commercial product. It can also import settings created for the Tunnelblick application.
-The reason for this error message is that the openvpn executable requires an updated version of the libuClibc library. For my build, this should be libuClibc-0.9.28.so.+
-Fortunately the package for this library can be located on the dd-wrt downloads page. Look for the "packages" folder at http://www.dd-wrt.com/dd-wrtv2/downloads.php, and retrieve the package named uclibc_0.9.28-6_mipsel.ipk.+
-Install this package on the jffs partition - refer to the ipkg documentation for details.+
-After installation, note down the exact path for libuClibc-0.9.28.so .. e.g. I installed mine at /jffs/sbin/liuClibc-0.9.8.so.+
-Now you need to ensure that when openvpn is launched as a daemon, the executing environment has the variable LD_PRELOAD set to point to the path to this library. In simpler language, what you need to do is insert the following line:+
- +
-export LD_PRELOAD=<replace_this_whole_angle_bracketed_region_with_your_full_path_to_library>+
- +
-at the start of the script that launches the openvpn server. openvpn will then use this library, instead of the older one that exists in the non-vpn OpenVPN distributions.+
- +
-19:13, 30 Jun 2006 (CEST) [http://www.dd-wrt.com/phpBB2/profile.php?mode=viewprofile&u=810 pagedude]+
- +
-===Connecting to DD-WRT OpenVPN Server via Mac Client===+
'''PROBLEM:''' When I used the sample client.conf file above, nothing happened when I clicked connect on Tunnelblick. '''PROBLEM:''' When I used the sample client.conf file above, nothing happened when I clicked connect on Tunnelblick.
Line 671: Line 396:
#!/bin/bash #!/bin/bash
 + sleep 2
ipconfig set tap0 DHCP ipconfig set tap0 DHCP
Line 797: Line 523:
# Silence repeating messages # Silence repeating messages
;mute 20 ;mute 20
 +
 +<br>
 +'''UPDATE Sept 1, 2009'''<br>
 +The most recent release of Tunnelblick is 3.0rc14. It seems as though the previously mention bash script does not work anymore. The following python script does work, however:
 +
 + #!/usr/bin/python
 + import os, sys
 + try:
 + tun_dev, tun_mtu, link_mtu = sys.argv[1:4]
 + except:
 + sys.exit(0)
 + if tun_dev[0:3] == 'tap'
 + os.system('/usr/sbin/ipconfig set "%s" DHCP' % os.environ['dev'])
===Can't Load DH Parameters=== ===Can't Load DH Parameters===
Line 808: Line 547:
Note: you ''must'' include new lines. Note: you ''must'' include new lines.
-[[Category:English documentation]]+===Connection reset by peer (WSAECONNRESET) (code=10054) ===
-[[Category:Advanced tutorials]]+If you received error when trying to connect to your VPN server verify the following:
 +* Make sure the tap-device was successfully "up'ed". It is, if you find it in the list when running "ifconfig" without further arguments. If it is not displayed in the list of available interfaces have a look at "Yet another evolution" above.
 +* Make sure the protocol is the same on the server and client, ie UDP/TCP
 +* Verify the port number is the same on the client and server; Default port is UDP 1194
 +* Check to see if the port is open on the server by using nMap or another utility
 + 
 +===Incoming Packet Rejected===
 +If you get incoming packets being rejected when trying to connect with the VPN client (OpenVPN) make sure that you are forwarding the 1194 port (if configured to use that port) to the proper server/router (usually 192.168.1.1).
 + 
 +Example TCP/UDP Rejection:
 +* [Date] TCP/UDP: Incoming packet rejected from 192.168.1.1:1194[2], expected peer address: w.x.y.z:1194 (allow this incoming source address/port by removing --remote or adding --float)
 + 
 +Port Forwarding is configured on v24 SP 2 under 'NAT / Qos'.
 + 
 +===Authenticate/Decrypt failure===
 + Error: Authenticate/Decrypt packet error: cipher final failed
 +If this happens to you, you probably have a mismatch in the configuration between server and client on the "cipher"-option. (E.g.: cipher AES-128-CB / cipher AES-256-CB)
 +This is not a problem of DD-WRT or OpenVPN but just a config issue which can happen if you follow some of those guidelines strictly without knowing what the config options mean.
 + 
 +[[Category:OpenVPN]]

Current revision

OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations, including road warrior access, home/office/campus telecommuting, WiFi security, secure branch office linking, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls.

Contents

[edit] Support

Refer to OpenVPN documentation for details on all OpenVPN features:

[edit] Getting OpenVPN

Install the OpenVPN client on the computer: Windows, Mac

Please note that it consists of one binary for both client and server connections, they are not separate packages.

[edit] OpenVPN authentication

You will have several possibilities to authenticate to an openvpn session. Some authentication methods are supported by the gui directly (should be preferred), others have to be set up in daemon mode. Which you will use depends on some things: how secure, easy to setup, easy to maintain

[edit] Public Key Infrastructure (PKI) [Certificates]

Pro-Linux article (German) about PKI security (13 Sep 2013): Current state of cryptography [English translation]

Follow these instructions to create the required certificates and keys. But there is also a Webmin module for linux servers to create your PKI infrastructure (OpenVPN CA). You begin by creating a key and certificate pair for the certificate authority (CA) you are establishing. Then for the server and each client, you create a private key and certificate pair and sign the certificates using the CA's key. Afterwards, you should have the following files:

ca.crt
ca.key
dh{n}.pem
server.crt
server.key

and a private key and certificate pair for each client. For example, if you have two clients, you should have:

client1.crt
client1.key
client2.crt
client2.key

Note: The CA private key (ca.key) is only to sign the certificates. Keep it secure and do not copy to the server nor clients.

OpenVPN certs must be generated with SHA auth: see this thread

[edit] Static Key

This method is only usable for connecting one client to a server!

On Linux you can create a pair of keys with:

openvpn --genkey --secret /home/"user"/static.key

For Windows, ensure openvpn is installed. To create a pair of keys go to:

Programs -> OpenVPN -> Generate a static openvpn key

Finally, copy the content of the keys to the ddwrt GUI static key field.

Also see: Static Key How-To and Create Static Keypair

[edit] OpenVPN in DD-WRT

Forum thread: OpenVPN server setup guide

This assumes DD-WRT with OpenVPN is installed on the router. OpenVPN is only available on units with at least 8mb flash (except the Broadcom VPN build). Instructions may vary based on version, as the following is for builds since 2011.

The DD-WRT GUI Server and Client modes' defaults should suffice for most users.

  1. Using the Web Interface, go to the "Services" tab and then the "VPN" tab (for older versions of dd-wrt go to the "Administration" tab and then the "Services" sub-tab).
  2. Enable OpenVPN Daemon or OpenVPN Client. If further options do not appear, click Apply Settings.
  3. Fill in needed parameters (see below). Everything else not mentioned here is taken care of automatically (e.g. firewall)
  4. Click Apply Settings.

Set up OpenVPN client where only specific traffic is routed via the VPN tunnel: Selective Routing Using DD-WRT & OpenVPN

[edit] CLI settings

[edit] Scramble Patch by clayface

These posts adds a patch to openvpn which introduces forms of scrambling to the packet payload of any OpenVPN connection. To use it you need both sides patched, server and client, and you introduce a new scramble password phrase in server and client config files

   “scramble password” – perform a simple xor operation the packet payload, using a string “password”, you choose password
   “scramble reverse” – This simply reverses all the data in the packet. This is enough to get past the regular expression detection in both China and Iran.
   “scramble xorptrpos” – This performs a xor operation, utilising the current position in the packet payload.
   “scramble obfuscate password” – This method is more secure. It utilises the 3 types of scrambling mentioned above. “password” is a string you choose. 

[edit] GUI: Client Mode

[edit] Fixed Parameters

There are default parameters that will always be written to the config file and which you cant change if you use GUI client mode:

ca /tmp/openvpncl/ca.crt
cert /tmp/openvpncl/client.crt
key /tmp/openvpncl/client.key
management 127.0.0.1 16
management-log-cache 50
verb 4
mute 5
syslog
writepid /var/run/openvpncl.pid
client
resolv-retry infinite
nobind
persist-key
persist-tun
script-security 2
tls-client
fast-io

[edit] Changeable Parameters

DD-WRT default settings in {}
OpenVPN config language in []

Server IP/Name (e.g. 192.168.1.1)
IP address/hostname of the OpenVPN server you want to connect to. [remote xxx]
Port
port which OpenVPN server is listening on. {1194} [port xxx]
Tunnel Device (TUN/TAP)
The mode of tunneling. TUN: routing (layer 3), TAP: bridgeing (layer 2. can be used for routing, too, but its not very common). [dev-type tun/tap]
Tunnel Protocoll (UDP/TCP)
The subprotocol the connection will use on the connection. {udp} [proto udp/tcp]
Encryption Cipher (None and Blowfish to AES512)
The encryption algorithm that will be used for the tunnel. Blowfish "fastest" to AES512 "safest". {AES128} [cipher xxx]
Hash Algorithm (None and MD4 to SHA512)
The hash algorithm that will be used. MD4: fastest (maybe unsafe) to SHA512. {SHA256} [auth xxx]
Advanced options
Leave defaults as is if you dont know what you are doing. {disabled} []
TLS Cipher
What encryption algorithm OpenVPN should use for encrypting its control channel. {disabled} []
LZO Compression
Enables compression over VPN. This might speedup the connection. Must be the same value as on server. {adaptive} [comp-lzo yes/no/adaptive/disabled]
NAT
Enable network address translation on the client side of the connection. Enables the NAT-firewall to protect clients. {disabled}
Bridge TAP to br0
Enable a transparent bridge across the tunnel to the local LAN. Works only in TAP mode with NAT disabled. {disabled}
Local IP Address
In cases you will not get an ip from the server. Not very common. {empty)
Subnet Mask
Subnet Mask for the IP Address.
TUN MTU Setting
set the mtu of the tunnel {1500} [tun-mtu xxx]
UDP Fragment across the tunnel
set mss-fix and fragmentaion accross the tunnel. {empty} [fragment xxx]
UDP MSS-Fix
= value of Fragment. Only usen with udp. should be set on one side only. [mssfix]
nsCertType verification
Checks to see if the remote server is using a valid type of certificate meant for OpenVPN connections. As this is a security feature of OpenVPN, it should be left enabled. {checked} []
TLS Auth Key
The static key OpenVPN should use for generating HMAC send/receive keys. {disabled} []
Additional Config
Any additional configurations you want to define for the VPN connection. {empty}
Policy based Routing
allow only special clients to use the tunnel. Add IPs in the form 0.0.0.0/0 to force clients to use the tunnel as default gateway. One line per IP. {} []
Public Server Cert
Certificate of OpenVPN CA (not the server's public cert) in pem form; only part between (and including) -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- is necessary; as it is stored in nvram, everything else from that file should be removed to conserve space.
CA Cert
CA certificate; also only part between 'BEGIN' and 'END' is required.
Private Client Key
Key associated with certificate above; should be kept secret because anybody who knows this key can successfully authenticate as this client.
DH PEM
Diffie Hellmann parameter.
Static Key
used for p2p links. No pki needed.

[edit] GUI: Server Configuration

This section describes how to configure an OpenVPN server that uses SSL certificates for client authentication, which is recommended. The method offers better security than using a static key and allows multiple clients to connect at the same time.

[edit] Fixed Parameters

There are default parameters in the DD-WRT config file that cannot be changed using the GUI server mode:

dh /tmp/openvpn/dh.pem
ca /tmp/openvpn/ca.crt
cert /tmp/openvpn/cert.pem
key /tmp/openvpn/key.pem
keepalive 10 120
verb 4
mute 5
log-append /var/log/openvpn
writepid /var/run/openvpnd.pid
management 127.0.0.1 5002
management-log-cache 50
mtu-disc yes
topology subnet
client-config-dir /tmp/openvpn/ccd
script-security 2
ifconfig-pool-persist /tmp/openvpn/ip-pool 86400
fast-io
passtos

[edit] Customizable Parameters

DD-WRT default settings in {}
OpenVPN config language in []

Start Type
use "System". "WAN Up" doesnt work. {}
Config via (GUI/config file)
GUI {}
Server Mode (TUN/TAP)
The mode of tunneling. TUN: routing (layer 3), TAP: bridging networks (layer 2). {} [dev-type tun/tap]
DHCP-Proxy mode
Only in bridge mode. Let the clients use the network dhcp server not the openvpn dhcp. {} []
Pool start Ip
1st ip of the ip pool used (Only in bridge mode). []
Pool end IP
Last ip of the ip pool used (Only in bridge mode). []
Gateway
Default gateway to use (Only in bridge mode). []
Network (e.g. 10.10.10.0)
Network to use for the tunnel (Only in routing mode). []
Netmask (e.g. 255.255.255.0)
Netmask of the used network. []
Block DHCP accross the tunnel
Dont allow DHCP requests across tunnel (Only in bridge mode).
Port
port which OpenVPN server listens on. {1194} [port xxx]
Tunnel Protocoll (UDP/TCP)
The subprotocol the connection will use on the real used tcp connection. {udp} [proto udp/tcp]
Encryption Cipher (None and Blowfish to AES512)
The encryption algorithm that will be used for the tunnel. Blowfish: fastest to AES512 safest. {AES128} [cipher xxx]
Hash Algorithm (None and MD4 to SHA512)
The hash algorithm that will be used. MD4: fastest (maybe unsafe) to SHA512. {SHA256} [auth xxx]
Advanced options
Leave defaults as is if you dont know what you are doing. {disabled}
LZO Compression
Enables compression over VPN. This might speedup the connection. Must be the same value as on server. {yes} [comp-lzo yes/no/adaptive/disabled]
Redirect default Gateway
Force the clients to use the tunnel as default gateway. {disabled} []
Allow Client to Client
Allow clients to see each other. {disabled} [client-to-client]
Allow duplicate cn
allow to use 1 client cert to use on multiple clients (security risc)
TUN MTU Setting
set the mtu of the tunnel {1500} [tun-mtu xxx]
MSS-Fix/Fragment across the tunnel
set mss-fix and fragmentaion accross the tunnel. {empty} [fragment xxx] [mssfix]
TLS Cipher
What encryption algorithm OpenVPN should use for encrypting its control channel. {disabled} []
TLS Auth Key
The static key OpenVPN should use for generating HMAC send/receive keys.
Client connect script
. {empty} []
Additional Config
Any additional configurations you want to define for the VPN connection. {empty}
CA Cert
Certificate of OpenVPN CA in pem form (usually ca.crt); only part between (and including) -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- is necessary; as it is stored in nvram, everything else from that file should be removed to conserve space.
Public Server Cert
Server certificate issued by CA for this particular router (usually server.crt); also only part between 'BEGIN' and 'END' is required.
Private Server Key
Key associated with certificate above (usually server.key); should be kept secret because anybody who knows this key can successfully authenticate client certificates.
DH PEM
Diffie Hellman parameters generated for the OpenVPN server (usually dh1024.pem).

[edit] Authentication with username and password

Certificates are nice, but having usernames and passwords can complement certificates. You can use the following scripts below to check for usernames/passwords.

Add this to the config on the server and set the right path for the script:

script-security 2
auth-user-pass-verify /path/to/your/script/verify.sh via-file

The script-security line is to resolve the issue where an external program may not be called due to setting of --script-security level The auth-user-pass-verify line enables the OpenVPN server to check the passed username and password by calling the script verify.sh and passing the username and password in a tmp file.

Every client will need to have this in its config file to connect:

auth-user-pass

This tells OpenVPN client to ask the user for username and password or s/he will not be able to log in. You can also use "--auth-user-pass" (instead of the line in the config file) on the command line.

I have split up the functions into separate files compared to predecessors (See page history). The verification done by the script may not work if OpenVPN is running in "daemon" mode (to be confirmed).

[Edit by Rocketboy235 Jan 21 2020] The script below has been updated to make use of SHA1 checksum instead of MD5 since the last time I created it back in mid 2018. However, SHA1 has been cracked since early 2019 so hopefully dd-wrt will come packaged with a more secure/newer hash tool that can be used. Also added instructions on how to setup the scripts for OpenVPN login authentication.

Instructions on how to use the below scripts

Add both scripts to your router and make sure to do chmod +x for each file. Then you can run Genhash.sh and pass the username and password arguments.

Example:

./genhash.sh NameOfMyUser MyLovelyPassword


This will generate a users file in /tmp and you can move it to whereever you like but you will need to update the Verify.sh script (line 14 ( begins with 'users=' )when you copy/paste this script) so that it points to that file when looking at the user list. For example, I place these scripts and my users file in /jffs/etc/openvpn/. Just note that if you save stuff in /tmp, you will lose them when the router reboots or loses power.

Verify.sh

 
#!/bin/sh
#verify.sh
#This script was made with via-file in mind

PATH=/usr/bin:/bin

#Function used for generating SHA1 hash value of password multiple times
function hashround() {
    local hash rest
    read hash rest
    printf '%s%s' "$hash" "$hash" | /usr/bin/sha1sum
}

#Location of the Approved Username/Password File
users="/location/of/the/file/for/users"

#Check to see if generated OpenVPN login file has any special characters
#Terminate script if special characters are used
if /bin/grep -q '[^-_a-zA-Z0-9]' "$1"
then 
	echo "Illegal characters found in username/password." >&2
	exit 1
fi

#1st line is the username
username=`/usr/bin/awk 'NR==1' "$1"`
#2nd line is the password
password=`/usr/bin/awk 'NR==2' "$1"`

#Generate SHA1 hash of given password and loop it 10 times before comparing with hash value in users file
hashpass=$(printf '%s%s' "$username" "$password" | /usr/bin/sha1sum \
           | hashround | hashround | hashround | hashround | hashround \
           | hashround | hashround | hashround | hashround | hashround \
           | /usr/bin/cut -d' ' -f1)
		
if /bin/grep -Fxq "$username:$hashpass" "$users"
then
	echo "User Authenticated." >&2
	exit 0
fi

echo "Login credentials failed." >&2
exit 1
 

Genhash.sh

#!/bin/sh
#genhash.sh
#Generate Hash for username/password
#Case sensitive and only allows a certain set of characters to be used

function hashround() {
    local hash rest
    read hash rest
    printf '%s%s' "$hash" "$hash" | /usr/bin/sha1sum
}

case "$1" in *[!-_a-zA-Z0-9]*) exit 1 ;; esac
case "$2" in *[!-_a-zA-Z0-9]*) exit 1 ;; esac

hashpass=$(printf '%s%s' "$1" "$2" | /usr/bin/sha1sum \
           | hashround | hashround | hashround | hashround | hashround \
           | hashround | hashround | hashround | hashround | hashround \
           | /usr/bin/cut -d' ' -f1)
		   
echo "Username: $1"
echo "Password: $2"
echo "Password (SHA1 Hashed): $hashpass"

echo "User added to approved user file which is saved in /tmp/users"
echo "$1:$hashpass" >> /tmp/users
 

[edit] Client Configuration

1) Copy the CA certificate and a private key and certificate pair to the client.

2) Create an OpenVPN configuration file on your client computer:

client
dev tap
proto udp
remote router-address 1194
resolv-retry infinite
nobind
persist-key
persist-tun
ca ca.crt
cert client1.crt
key client1.key
ns-cert-type server
comp-lzo
verb 3

Replace router-address in the fourth line with your router's IP address or host name and, obviously, use the appropriate file names in the script for the client's certificate and key. On Windows, save this script using notepad as a file with extension .ovpn and copy it into \Program Files\OpenVPN\config (along with the files ca.crt, clientX.crt and clientX.key created earlier.)

Notes:

  • If you need to use TCP instead of UDP, set the protocol to tcp-client. Clients must use the same protocol that the server does.
  • Client config also need match these server parameters: dev (tun/tap), cipher, auth, comp-lzo, tun-mtu.
  • Mac OS X users and Linux users using TAP need to add the line
up "./vpn-up.sh"

to the configuration file and create a script file vpn-up.sh in the same directory as the configuration file with the following contents.

On Mac:

#!/bin/bash 
sleep 2
ipconfig set $1 DHCP

On Linux:

#!/bin/bash 
sleep 2
dhclient $1 & 

This script configures the TAP interface to request an IP address using DHCP. Make sure to make the script executable with 'chmod 755 vpn-up.sh'.

3) Use the configuration file you just created with whatever OpenVPN client software you're using to establish a connection to your router.

If everything works, you will be connected to your internal LAN. If your router is running a DHCP server, the TAP interface will be assigned an IP address on your internal LAN. At this point, you just connect to your home PC the same way you would do it from inside your LAN.

[edit] Daemon Mode/Config File

Bridge 2 Networks
Route 2 Networks

[edit] Troubleshooting

[edit] FAQ

[edit] MTU

One verycommon problem is the wrong setting of the mtu/fragment/mss-fix values. Ethernet's max frame size is 1500. In most cases where the Router is the gateway and the vpn connects to the outside world the values must be changed. WAN connections in general will have a lower frame size so the default setting will result in a dropping connection. mtu/fragment must be set the same on both sides!

On tcp connections only mtu can be set. Try setting the mtu to 1300 and see if it works.

On udp connections enable mss-fix on one side of the link. Lower the fragemt size to 1300 and try if its working.

In both cases when the link is working u can try to raise the values again to the maximum which will be working.

[edit] Logs

logs are written to syslog and can be seen in the GUI: Status -> OpenVPN (not in daemon and script mode)

[edit] Correct time

OpenVPN requires client and server to have more or less synchronized time. Therefore make sure that router has correct time. To check it use command date and if you get info about year 1970, you should enable NTP client. Also, ntp server has to be outside of your VPN as time should be corrected before VPN is established. If you have syslog enabled (to local server, or the server outside your VPN), errors like TLS Error: Unroutable control packet received from server_ip:1194 may indicate this problem. (This error message may appear if your certificates are not valid or have expired, too.) If you get an error message saying that your certificate is not yet valid, set the dd-wrt clock to UTC time (in the first configuration page).

To set the time manually connect via telnet or ssh and issue the following command at the prompt:
date MMDDHHMMYYYY

[edit] Connecting to DD-WRT OpenVPN Server via Mac Client

Currently, there are two OpenVPN clients for OS X

Viscosity has a more user friendly GUI but is a commercial product. It can also import settings created for the Tunnelblick application.

PROBLEM: When I used the sample client.conf file above, nothing happened when I clicked connect on Tunnelblick.

Tunnelblick is a GUI OpenVPN application for the Mac. The last official release is 2.0.1, but I am going to explain how to connect using version 3.0rc3. This version has everything in one app and requires no extra components to be installed.

NOTE: I used certificates to connect my MacBook Pro to the OpenVPN server. You can find documentation on how to do this further up in this page. Remember to place your certificate files in the same directory as the client.conf file. Tunnelblick looks for the files in ~/Library/openvpn.

Download Tunnelblick and drag it to the Applications folder. It will say that you don't have a client.conf file and will make one for you. You can examine the sample client.conf file that Tunnelblick makes and find that it does a few things differently than the example provided above. Set up your client.conf file using the sample I have provided below, and Tunnelblick should connect properly now.

The file I have provided is the same as the sample, except with a few things disabled and a few things added to make it do what we want. The reason I disabled a few things using the # line is that I didn't want to delete anything, so I just disabled them.

You might notice that the command

up "./vpn-up.sh"

This is a fix that I found here.

You will need to make a script called vpn-up.sh and place it in the same directory as the client.conf file. Make the files contents:

#!/bin/bash
sleep 2
ipconfig set tap0 DHCP

client.conf:

##############################################
# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server.     #
#                                            #
# This configuration can be used by multiple #
# clients, however each client should have   #
# its own cert and key files.                #
#                                            #
# On Windows, you might want to rename this  #
# file so it has a .ovpn extension           #
##############################################

# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client

# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
dev tap 

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel
# if you have more than one.  On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
#dev-node MyTap
 
# Are we connecting to a TCP or
# UDP server?  Use the same setting as
# on the server.
proto tcp

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote xxxxxxxxx.dyndns.org 1194 

# Choose a random host from the remote
# list for load-balancing.  Otherwise
# try hosts in the order specified.
#remote-random 

# Keep trying indefinitely to resolve the
# host name of the OpenVPN server.  Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite

# Most clients don't need to bind to
# a specific local port number.
nobind

# Downgrade privileges after initialization (non-Windows only)
user nobody
group nobody

# Try to preserve some state across restarts.
persist-key
persist-tun

# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here.  See the man page
# if your proxy server requires
# authentication.
#http-proxy-retry # retry on connection failures
#http-proxy [proxy server] [proxy port #]

# Wireless networks often produce a lot
# of duplicate packets.  Set this flag
# to silence duplicate packet warnings.
mute-replay-warnings

# SSL/TLS parms.
# See the server config file for more
# description.  It's best to use
# a separate .crt/.key file pair
# for each client.  A single ca
# file can be used for all clients.
ca ca.crt
cert client1.crt
key client1.key

up "./vpn-up.sh"

# Verify server certificate by checking
# that the certicate has the nsCertType
# field set to "server".  This is an
# important precaution to protect against
# a potential attack discussed here:
# http://openvpn.net/howto.html#mitm

# To use this feature, you will need to generate
# your server certificates with the nsCertType
# field set to "server".  The build-key-server
# script in the easy-rsa folder will do this.
ns-cert-type server

# If a tls-auth key is used on the server
# then every client must also have the key.
#tls-auth ta.key 1

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
#cipher x

# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo

# Set log file verbosity.
verb 3

# Silence repeating messages
;mute 20


UPDATE Sept 1, 2009
The most recent release of Tunnelblick is 3.0rc14. It seems as though the previously mention bash script does not work anymore. The following python script does work, however:

#!/usr/bin/python
import os, sys
try:
    tun_dev, tun_mtu, link_mtu = sys.argv[1:4]
except:
    sys.exit(0)
if tun_dev[0:3] == 'tap'
    os.system('/usr/sbin/ipconfig set "%s" DHCP' % os.environ['dev'])

[edit] Can't Load DH Parameters

If you get the following:

Tue Jan 23 03:03:05 2007 OpenVPN 2.0.7 mipsel-unknown-linux [SSL] [LZO] [EPOLL] built on Jan 15 2007
Tue Jan 23 03:03:05 2007 Cannot load DH parameters from dh1024.pem: error:0906D064:lib(9):func(109):reason(100)
Tue Jan 23 03:03:05 2007 Exiting

you should check your certificates. Did you paste them correctly?

Note: you must include new lines.

[edit] Connection reset by peer (WSAECONNRESET) (code=10054)

If you received error when trying to connect to your VPN server verify the following:

  • Make sure the tap-device was successfully "up'ed". It is, if you find it in the list when running "ifconfig" without further arguments. If it is not displayed in the list of available interfaces have a look at "Yet another evolution" above.
  • Make sure the protocol is the same on the server and client, ie UDP/TCP
  • Verify the port number is the same on the client and server; Default port is UDP 1194
  • Check to see if the port is open on the server by using nMap or another utility

[edit] Incoming Packet Rejected

If you get incoming packets being rejected when trying to connect with the VPN client (OpenVPN) make sure that you are forwarding the 1194 port (if configured to use that port) to the proper server/router (usually 192.168.1.1).

Example TCP/UDP Rejection:

  • [Date] TCP/UDP: Incoming packet rejected from 192.168.1.1:1194[2], expected peer address: w.x.y.z:1194 (allow this incoming source address/port by removing --remote or adding --float)

Port Forwarding is configured on v24 SP 2 under 'NAT / Qos'.

[edit] Authenticate/Decrypt failure

Error: Authenticate/Decrypt packet error: cipher final failed

If this happens to you, you probably have a mismatch in the configuration between server and client on the "cipher"-option. (E.g.: cipher AES-128-CB / cipher AES-256-CB) This is not a problem of DD-WRT or OpenVPN but just a config issue which can happen if you follow some of those guidelines strictly without knowing what the config options mean.