How to setup IPSEC tunnel with Watchguard Firebox with NAT-T enabled

ttblum · Nov 16, 2011, 8:19 PM

Hello,

I currently have an IPSec tunnel setup between by pfSense 2.0 RC3 and a Watchguard Firebox. The tunnel seems to be unstable, and the last time it went down I noticed the pfSense firewall was blocking UDP traffic on port 4500 - I believe UDP port 4500 is Nat-Traversal.

I currently have a firewall rule on the WAN interface allowing UDP 500 traffic, do I also need to add a rule allowing UDP port 4500 traffic?

Thanks,

Todd

lint · Nov 21, 2011, 6:14 PM

@ttblum:

do I also need to add a rule allowing UDP port 4500 traffic?

That depends on if you are using NAT-T.

Look in your tunnel configuration to see if you have NAT Traversal enabled in pfSense. It is in the advanced options at the bottom of the phase 1 policy.

If both firewalls have NAT-T on, then you will need to allow access over UDP 4500, or disable it on both.