VPNC
From DD-WRT Wiki
vpnc is supposed to work with:
- Cisco VPN concentrator 3000 Series
- Cisco IOS routers
- Cisco PIX / ASA Zecurity Appliances
- Juniper/Netscreen
This describes how to use DD-WRT to connect to a Cisco VPN Concentrator using vpnc without auto-reconnect and without connect on startup
This "script" without reconnect is mainly for people to test vpnc and find out the correct settings before they use the script with auto-reconnect. If you want your router to automatically reconnect on connection loss see further down
There is currently no gui for this, but don't worry, it won't be complicated. This script also automatically reconnects, if your vpn connection gets disconnected
To let your router connect to the vpn concentrator and share the connection with its clients follow the steps below:
- You need to flash DD-WRT VPN build after 08/18/07 (I recommend latest v24 vpn).
- Paste the code below into a text editor and adjust line 2 - 6.
- Open a Webbrowser, type the IP of your router, then go to Administration -> Commands
- Paste the code adjusted in Step 2 into the commands box, then click 'Save Startup'
- Reboot your router
- Log in via telnet and enter: vpnc /tmp/etc/vpnc/vpn.conf
- To share the vpn tunnel with the connected pc's, enter the following via telnet:
iptables -A FORWARD -o tun0 -j ACCEPT iptables -A FORWARD -i tun0 -j ACCEPT iptables -t nat -A POSTROUTING -o tun0 -j MASQUERADE
To disconnect the tunnel, type vpnc-disconnect. Step 6+7 have to be redone after every disconnect or reboot
If you have any comment or question on this, you can PM me in the DD-WRT Forum (Username: alain)
#!/bin/sh vpn_concentrator="host" ##enter ip or hostname of your Ipsec vpn concentrator vpn_groupname="grid" ##enter the group name here vpn_grouppasswd="grppasswd" ##enter the group password here vpn_username="username" ##enter your username here vpn_password="password" ##enter your password here #--do not edit this-- #Written by Alain R. (alainr [AT] gmx.de) 27.Sep.2007 vpnc-disconnect rm -f /tmp/etc/vpnc/vpn.conf mkdir /tmp/etc/vpnc echo " IPSec gateway $vpn_concentrator IPSec ID $vpn_groupname IPSec secret $vpn_grouppasswd Xauth username $vpn_username Xauth password $vpn_password " >> /tmp/etc/vpnc/vpn.conf
This describes how to use DD-WRT to connect to a Cisco VPN Concentrator using vpnc with auto-reconnect
This script does not give out any (useful) error nessages. If you have trouble establishing a tunnel, first look at the script without reconnect
There is currently no gui for this, but don't worry, it won't be complicated.
This script also automatically reconnects, if your vpn connection gets disconnected
To let your router connect to the vpn concentrator and share the connection with its clients follow the steps below:
- You need to flash DD-WRT VPN build after 08/18/07 (I recommend latest v24 vpn).
- Paste the code below into a text editor and adjust line 5 - 11.
- Open a Webbrowser, type the IP of your router, then go to Administration -> Commands
- Paste the code adjusted in Step 2 into the commands box, then click 'Save Startup'
- Reboot your router
If everything worked fine, your router has now established a vpn tunnel.
If you have any comment or question on this, you can PM me in the DD-WRT Forum (Username: alain)
mkdir /tmp/etc/vpnc rm -f /tmp/etc/vpnc/vpnc.sh echo ' #!/bin/sh vpn_concentrator="host" ##enter ip or hostname of your Ipsec vpn concentrator vpn_keepalive_host1="keepalive1" ##enter the ip or hostname of a computer that is only reachable if vpn connection is established. vpn_keepalive_host2="keepalive2" ##enter the ip or hostname of a computer that is only reachable if vpn connection is established. vpn_groupname="grid" ##enter the group name here vpn_grouppasswd="grppasswd" ##enter the group password here vpn_username="username" ##enter your username here vpn_password="password" ##enter your password here #--do not edit this-- #Written by Alain R. (alainr [AT] gmx.de) 28.Sep.2007 vpnc-disconnect rm -f /tmp/etc/vpnc/vpn.conf echo " IPSec gateway $vpn_concentrator IPSec ID $vpn_groupname IPSec secret $vpn_grouppasswd Xauth username $vpn_username Xauth password $vpn_password " >> /tmp/etc/vpnc/vpn.conf pingtest1 () { ping -q -c1 $param1 >> /dev/null if [ "$?" == "0" ]; then echo 0 #reachable else echo 1 #not reachable fi } pingtest2 () { ping -q -c2 $param2 >> /dev/null if [ "$?" == "0" ]; then echo 0 #reachable else echo 1 #not reachable fi } while [ true ]; do param1=$vpn_concentrator; if [ "`pingtest1`" == "0" ]; then #Vpn concentrator reachable doloop=1; while [ $doloop -gt 0 ]; do param1=$vpn_keepalive_host1; if [ "`pingtest1`" == "0" ]; then sleep 300 else param2=$vpn_keepalive_host2; if [ "`pingtest2`" == "0" ]; then sleep 300 else doloop=0; vpnc-disconnect vpnc /tmp/etc/vpnc/vpn.conf --dpd-idle 0 sleep 1 if [ "`pingtest1`" != "0" ]; then sleep 10 fi tundev="`ifconfig |grep tun |cut -b 1-4`" iptables -A FORWARD -o $tundev -j ACCEPT iptables -A FORWARD -i $tundev -j ACCEPT iptables -t nat -A POSTROUTING -o $tundev -j MASQUERADE sleep 9 fi fi done else sleep 10; fi done return 0; ' >> /tmp/etc/vpnc/vpnc.sh chmod 700 /tmp/etc/vpnc/vpnc.sh /tmp/etc/vpnc/vpnc.sh&
FAQ Frequently asked Questions
- Can some attacker steal my VPN password
Yes, if you don't secure your router...