extrim/vpnclient repository overview

⁠l2tp-ipsec-vpnclient

A tiny Debian based docker image to quickly setup an L2TP over IPsec VPN client w/ PSK.

⁠Motivation

Does your office or a client have a VPN server already setup and you just need to connect to it? Do you use Linux and are jealous that the one thing a MAC can do better is quickly setup this kind of VPN? Then here is all you need:

1. VPN Server Address
2. Pre Shared Key
3. Username
4. Password

⁠Run

Setup environment variables for your credentials and config:

export VPN_SERVER_IP='1.2.3.4'
export VPN_PSK='pre shared key'
export VPN_USERNAME='[email protected]'
export VPN_PASSWORD='pass'

Now run it (you can daemonize of course after debugging):

docker run --rm -it --privileged --net=host \
           -e VPN_SERVER_IP \
           -e VPN_PSK \
           -e VPN_USERNAME \
           -e VPN_PASSWORD \
              extrim/vpnclient

⁠Route

From the host machine configure traffic to route through VPN link:

# confirm the ppp0 link and get the peer e.g. (192.0.2.1) IPV4 address
ip a show ppp0
# route traffic for a specific target ip through VPN tunnel address
sudo route add 1.2.3.4 via 192.0.2.1 dev ppp0
# route all traffice through VPN tunnel address
sudo route add default dev ppp0
# when your done add your normal routes and delete the VPN routes
# or just `docker stop` and you'll probably be okay

⁠Test

You can see if your IP address changes after adding appropriate routes e.g.:

curl ifconfig.me

⁠TODO

• See if this can work without privileged and net=host modes to be more portable

⁠References

• ubergarm/l2tp-ipsec-vpn-client⁠
• Stanback/alpine-strongswan-vpn⁠
• hwdsl2/docker-ipsec-vpn-server⁠