Tag Archives: L2TP

L2TP (Ubuntu) server setup for iOS clients

For you road warriors who wish to set up their own VPN to secure their traffic when using any untrusted/unprotected networks (“free” WiFi?) when travelling, this would be the thing you use: a trusted VPN setup.

While I did dabble with OpenVPN sometime back, protocols like L2TP would be more commonly supported, especially on the “venerable” iOS device (iPhone, iPod Touch, iPad), and on Windoze machines, Android, etc.

This post will be on what you’ll need to setup a L2TP server in Ubuntu for iOS devices to connect to. The server is assumed to be directly accessible from the internet. Some of the stuff are taken from other places, for my own reference here. There’s also a great write up on IPsec over at Steve Friedl’s Unixwiz.net Tech Tips site, for you geeks who actually want to understand a little regarding what you’re using (high five!).

The L2TP server setup mainly comprises of three parts actually (surprise!). The L2TP daemon, IPsec daemon and the PPP daemon (providing DHCP services).

Main steps:

  1. install openswan (for IPsec), xl2tpd (L2TP) and ppp
  2. configure
  3. configure the (Linux) kernel to turn on IP forwarding, and IP masquerading if the iptables firewall is on
  4. configure the device itself
  5. take a break, have a pina colada or something
  6. profit!

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