Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am having trouble connecting to a L2TP IPSec VPN when I use my wireless router. I have a LinkSys WRT54GL v1.1 wireless router with the most current version of tomato (1.28).

I have no issues connecting to the VPN server when I connect directly to the modem. I am using Windows 7 and its built-in VPN client.

Any ideas?

share|improve this question

Enable the router's "VPN Passthrough" feature, which should be in the Advanced settings somewhere.

Of course, if you'd like to (or need to) get away from IPSec, I highly recommend OpenVPN which works without the need to enable the "VPN Passthrough" option:

  OpenVPN (free, open source, userland VPN solution)

share|improve this answer
I am using Tomato there is no vpn passthrough option – Johnny Apr 30 '11 at 4:38
If IPSec is not supported, then a solution like the one that OpenVPN provides will be needed. IPSec works differently than most applications, which is why special support by routers may be needed. – Randolf Richardson May 2 '11 at 5:16
OpenVPN is great. Just not built into windows by default. But easily obtained and installed. – Matt H Feb 11 '13 at 20:23

No problem,

VPN passthrough just opens up your firewall with these options for IPSEC.

You need firewall rules to allow udp dest ports 500 & 1701. protocol gre/esp & ah in.

In iptables it would basically be this:

iptables -A FORWARD -p udp -m multiport --dports 500,1701 -j ACCEPT
iptables -A FORWARD -p gre -j ACCEPT
iptables -A FORWARD -p esp -j ACCEPT
iptables -A FORWARD -p ah -j ACCEPT

Of course that allows anyone to access your VPN potentially, so I'd recommend you filter that further by IP range if you can.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.