VPNC

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/tmp/etc/vpnc/vpnc.sh&</pre> /tmp/etc/vpnc/vpnc.sh&</pre>
-==FAQ Frequently asked Questions==+== Multi-Site VPN ==
-* Can I VPN into multiple sites?+ mkdir /tmp/etc/vpnc
-Yes you can, you need to keep in mind the following VPNC arguments:+
-# Local Port 0 (makes it take a random port, very important otherwise all instances try to bind to 500)+ # get rid of left over scripts
-# Interface name tun[n] (each connection needs to be set-up on a separate interface, vpnc handles creating and destroying these so you need not worry about anything else)+ if [ -f /tpm/etc/vpnc/vpnc-tun0.sh ]; then
-I leave the script writing to you, one last thing to keep in mind, vpnc-disconnect disconnects ALL instances of the daemon, make sure you record the process ID for each one and disconnect things accordingly if you need to reset one of the tunnels, this way you dont reset all.+ rm -f /tmp/etc/vpnc/vpnc-tun0.sh
 + fi
 + if [ -f /tpm/etc/vpnc/vpnc-tun1.sh ]; then
 + rm -f /tmp/etc/vpnc/vpnc-tun1.sh
 + fi
 +
 + # get rid of any leftover connections
 + vpnc-disconnect
 +
 + echo '
 + #!/bin/sh
 + vpnc_interface="tun0"
 + vpnc_concentrator="87.xx.xxx.xxx"
 + vpnc_keepalive_host="10.10.xx.x"
 + vpnc_groupname="xxxxxx"
 + vpnc_grouppasswd="xxxxxx"
 + vpnc_username="xxxxxx"
 + vpnc_password="xxxxxx"
 +
 + sleep_short=10
 + sleep_long=300
 + pid=0
 +
 + # remove any old config files
 + rm -f /tmp/etc/vpnc/vpnc-tun0.conf
 +
 + # create the new config file
 + echo "
 + Local Port 0
 + Interface name ${vpnc_interface}
 + IPSec gateway ${vpnc_concentrator}
 + IPSec ID ${vpnc_groupname}
 + IPSec secret ${vpnc_grouppasswd}
 + Xauth username ${vpnc_username}
 + Xauth password ${vpnc_password}
 + " > /tmp/etc/vpnc/vpnc-tun0.conf
 +
 + alive () {
 + ping -q -c1 ${1} >> /dev/null
 + if [ "$?" == "0" ]; then
 + return 0
 + else
 + return 1
 + fi
 + }
 +
 + while [ true ]; do
 + doloop=1;
 + while [ ${doloop} -gt 0 ]; do
 + alive ${vpnc_keepalive_host}
 + if [ "$?" == "0" ]; then
 + sleep ${sleep_long}
 + else
 + doloop=0;
 +
 + if [ ${pid} != "0" ]; then
 + exec kill ${pid}
 + fi
 + # establish the link
 + vpnc /tmp/etc/vpnc/vpnc-tun0.conf --dpd-idle 0
 + # record the process id
 + pid=$!
 + sleep 1
 +
 + alive ${vpnc_keepalive_host}
 + if [ "$?" != "0" ]; then
 + sleep ${sleep_short}
 + fi
 +
 + iptables -A FORWARD -o ${vpnc_interface} -j ACCEPT
 + iptables -A FORWARD -i ${vpnc_interface} -j ACCEPT
 + iptables -t nat -A POSTROUTING -o ${vpnc_interface} -j MASQUERADE
 + sleep ${sleep_short}
 + fi
 + done
 + done
 +
 + return 0;
 + ' >> /tmp/etc/vpnc/vpnc-tun0.sh
 + chmod 700 /tmp/etc/vpnc/vpnc-tun0.sh
 + /tmp/etc/vpnc/vpnc-tun0.sh&
 +
 + echo '
 + #!/bin/sh
 + vpnc_interface="tun1"
 + vpnc_concentrator="69.xx.xxx.xxx"
 + vpnc_keepalive_host="192.168.xxx.x"
 + vpnc_groupname="xxxxxx"
 + vpnc_grouppasswd="xxxxxx"
 + vpnc_username="xxxxxx"
 + vpnc_password="xxxxxx"
 +
 + sleep_short=10
 + sleep_long=300
 + pid=0
 +
 + # remove any old config files
 + rm -f /tmp/etc/vpnc/vpnc-tun1.conf
 +
 + # create the new config file
 + echo "
 + Local Port 0
 + Interface name ${vpnc_interface}
 + IPSec gateway ${vpnc_concentrator}
 + IPSec ID ${vpnc_groupname}
 + IPSec secret ${vpnc_grouppasswd}
 + Xauth username ${vpnc_username}
 + Xauth password ${vpnc_password}
 + " > /tmp/etc/vpnc/vpnc-tun1.conf
 +
 + alive () {
 + ping -q -c1 ${1} >> /dev/null
 + if [ "$?" == "0" ]; then
 + return 0
 + else
 + return 1
 + fi
 + }
 +
 + while [ true ]; do
 + doloop=1;
 + while [ ${doloop} -gt 0 ]; do
 + alive ${vpnc_keepalive_host}
 + if [ "$?" == "0" ]; then
 + sleep ${sleep_long}
 + else
 + doloop=0;
 +
 + if [ ${pid} != "0" ]; then
 + exec kill ${pid}
 + fi
 + # establish the link
 + vpnc /tmp/etc/vpnc/vpnc-tun1.conf --dpd-idle 0
 + # record the process id
 + pid=$!
 + sleep 1
 +
 + alive ${vpnc_keepalive_host}
 + if [ "$?" != "0" ]; then
 + sleep ${sleep_short}
 + fi
 +
 + iptables -A FORWARD -o ${vpnc_interface} -j ACCEPT
 + iptables -A FORWARD -i ${vpnc_interface} -j ACCEPT
 + iptables -t nat -A POSTROUTING -o ${vpnc_interface} -j MASQUERADE
 + sleep ${sleep_short}
 + fi
 + done
 + done
 +
 + return 0;
 + ' >> /tmp/etc/vpnc/vpnc-tun1.sh
 + chmod 700 /tmp/etc/vpnc/vpnc-tun1.sh
 + /tmp/etc/vpnc/vpnc-tun1.sh&
 + 
 +==FAQ Frequently asked Questions==
* Can some attacker steal my VPN password * Can some attacker steal my VPN password

Revision as of 20:30, 14 August 2008

vpnc is supposed to work with:

  • Cisco VPN concentrator 3000 Series
  • Cisco IOS routers
  • Cisco PIX / ASA Zecurity Appliances
  • Juniper/Netscreen

Contents

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:

  1. You need to flash DD-WRT VPN build after 08/18/07 (I recommend latest v24 vpn).
  2. Paste the code below into a text editor and adjust line 2 - 6.
  3. Open a Webbrowser, type the IP of your router, then go to Administration -> Commands
  4. Paste the code adjusted in Step 2 into the commands box, then click 'Save Startup'
  5. Reboot your router
  6. Log in via telnet and enter: vpnc /tmp/etc/vpnc/vpn.conf
  7. 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

I added also the next rule to share the tunnel tun0 with the LAN connected in br0 interface and added the DNS and WIN servers from my VPN to the local computer connected to LAN:

iptables -A FORWARD -i br0 -j ACCEPT


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

If your VPN also requires your NTDomain to be submitted, modify the above 2 sections to include: (This also applies to the 'persistent' section below)
under "vpn_password"

vpn_domain="domain"           ##enter your NTDomain here

and under "Xauth password $vpn_password" add:

Domain $vpn_domain

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:

  1. You need to flash DD-WRT VPN build after 08/18/07 (I recommend latest v24 vpn).
  2. Paste the code below into a text editor and adjust line 5 - 11.
  3. Open a Webbrowser, type the IP of your router, then go to Administration -> Commands
  4. Paste the code adjusted in Step 2 into the commands box, then click 'Save Startup'
  5. 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&

Multi-Site VPN

mkdir /tmp/etc/vpnc

# get rid of left over scripts
if [ -f /tpm/etc/vpnc/vpnc-tun0.sh ]; then
	rm -f /tmp/etc/vpnc/vpnc-tun0.sh
fi
if [ -f /tpm/etc/vpnc/vpnc-tun1.sh ]; then
	rm -f /tmp/etc/vpnc/vpnc-tun1.sh
fi

# get rid of any leftover connections
vpnc-disconnect

echo '
#!/bin/sh
vpnc_interface="tun0"
vpnc_concentrator="87.xx.xxx.xxx"
vpnc_keepalive_host="10.10.xx.x"
vpnc_groupname="xxxxxx"
vpnc_grouppasswd="xxxxxx"
vpnc_username="xxxxxx"
vpnc_password="xxxxxx"

sleep_short=10
sleep_long=300
pid=0

# remove any old config files
rm -f /tmp/etc/vpnc/vpnc-tun0.conf

# create the new config file
echo "
Local Port 0
Interface name ${vpnc_interface}
IPSec gateway ${vpnc_concentrator}
IPSec ID ${vpnc_groupname}
IPSec secret ${vpnc_grouppasswd}
Xauth username ${vpnc_username}
Xauth password ${vpnc_password}
" > /tmp/etc/vpnc/vpnc-tun0.conf

alive () {
	ping -q -c1 ${1} >> /dev/null
	if [ "$?" == "0" ]; then
		return 0
	else
		return 1
	fi
}

while [ true ]; do
	doloop=1;
	while [ ${doloop} -gt 0 ]; do
		alive ${vpnc_keepalive_host}
		if [ "$?" == "0" ]; then
			sleep ${sleep_long}
		else
			doloop=0;
			
			if [ ${pid} != "0" ]; then
				exec kill ${pid}
			fi
			# establish the link
			vpnc /tmp/etc/vpnc/vpnc-tun0.conf --dpd-idle 0
			# record the process id
			pid=$!
			sleep 1
			
			alive ${vpnc_keepalive_host}
			if [ "$?" != "0" ]; then
				sleep ${sleep_short}
			fi
			
			iptables -A FORWARD -o ${vpnc_interface} -j ACCEPT
			iptables -A FORWARD -i ${vpnc_interface} -j ACCEPT
			iptables -t nat -A POSTROUTING -o ${vpnc_interface} -j MASQUERADE
			sleep ${sleep_short}
		fi
	done
done

return 0;
' >> /tmp/etc/vpnc/vpnc-tun0.sh
chmod 700 /tmp/etc/vpnc/vpnc-tun0.sh
/tmp/etc/vpnc/vpnc-tun0.sh&

echo '
#!/bin/sh
vpnc_interface="tun1"
vpnc_concentrator="69.xx.xxx.xxx"
vpnc_keepalive_host="192.168.xxx.x"
vpnc_groupname="xxxxxx"
vpnc_grouppasswd="xxxxxx"
vpnc_username="xxxxxx"
vpnc_password="xxxxxx"

sleep_short=10
sleep_long=300
pid=0

# remove any old config files
rm -f /tmp/etc/vpnc/vpnc-tun1.conf

# create the new config file
echo "
Local Port 0
Interface name ${vpnc_interface}
IPSec gateway ${vpnc_concentrator}
IPSec ID ${vpnc_groupname}
IPSec secret ${vpnc_grouppasswd}
Xauth username ${vpnc_username}
Xauth password ${vpnc_password}
" > /tmp/etc/vpnc/vpnc-tun1.conf

alive () {
	ping -q -c1 ${1} >> /dev/null
	if [ "$?" == "0" ]; then
		return 0
	else
		return 1
	fi
}

while [ true ]; do
	doloop=1;
	while [ ${doloop} -gt 0 ]; do
		alive ${vpnc_keepalive_host}
		if [ "$?" == "0" ]; then
			sleep ${sleep_long}
		else
			doloop=0;
			
			if [ ${pid} != "0" ]; then
				exec kill ${pid}
			fi
			# establish the link
			vpnc /tmp/etc/vpnc/vpnc-tun1.conf --dpd-idle 0
			# record the process id
			pid=$!
			sleep 1
			
			alive ${vpnc_keepalive_host}
			if [ "$?" != "0" ]; then
				sleep ${sleep_short}
			fi
			
			iptables -A FORWARD -o ${vpnc_interface} -j ACCEPT
			iptables -A FORWARD -i ${vpnc_interface} -j ACCEPT
			iptables -t nat -A POSTROUTING -o ${vpnc_interface} -j MASQUERADE
			sleep ${sleep_short}
		fi
	done
done

return 0;
' >> /tmp/etc/vpnc/vpnc-tun1.sh
chmod 700 /tmp/etc/vpnc/vpnc-tun1.sh
/tmp/etc/vpnc/vpnc-tun1.sh&

FAQ Frequently asked Questions

  • Can some attacker steal my VPN password

Yes, if you don't secure your router...

  • Is it possible to get this to work when using the router as a wireless repeater?

Yes, I use it here on a wireless repeater. If you experience problems, flash latest v24 and follow Wlan Repeater.

  • I cannot connect if my password contains ", $, `, or \.

The reason is that the shell always interprets these characters (even between quotation marks). If your password contains such characters, just put a \ (escape character) before each of the above characters. If your password is for example abc$123\xyz you need to enter abc\$123\\xyz

  • Can I use split-tunneling to access my local network (and local internet connection) while still accessing my corporate network via VPN tunnel?

Yes. On a Windows machine (which I have tested), you need to edit the TCP/IP configuration and explicitly identify your DNS servers via IP. Add in your corporate DNS server first in the list, then your ISP DNS servers. If you access corporate SMB network shares, be sure to add in your corporate WINS server.

For split tunneling, use the following code:

#!/bin/sh
# This is a wrapper for the vpnc-script overriding some variables needed
# for setting up split-tunneling
# this effectively disables changes to /etc/resolv.conf
INTERNAL_IP4_DNS=

# This sets up split networking regardless of the concentrators specifications.
# You can add as many routes as you want, but you must set the counter
# CISCO_SPLIT_INC accordingly.  All requests to IP ranges NOT listed
# in the code below will NOT go though the VPN tunnel.

CISCO_SPLIT_INC=2
CISCO_SPLIT_INC_0_ADDR=147.0.0.0  #IP range to go into first tunnel
CISCO_SPLIT_INC_0_MASK=255.0.0.0  #Subnet Mask for first tunnel
CISCO_SPLIT_INC_0_MASKLEN=8         #Mask length
CISCO_SPLIT_INC_0_PROTOCOL=0
CISCO_SPLIT_INC_0_SPORT=0
CISCO_SPLIT_INC_0_DPORT=0
CISCO_SPLIT_INC_1_ADDR=172.0.0.0    #IP range to go into the second tunnel
CISCO_SPLIT_INC_1_MASK=255.0.0.0     #Subnet mask
CISCO_SPLIT_INC_1_MASKLEN=8           #Mask length
CISCO_SPLIT_INC_1_PROTOCOL=0
CISCO_SPLIT_INC_1_SPORT=0
CISCO_SPLIT_INC_1_DPORT=0

# run the original script
. /etc/vpnc/vpnc-script