Published on (  See this if you're having trouble printing code
examples  FreeBSD Basics Cryptosystems: Debugging IPSec  by Dru
Lavigne  In the last article, we configured the files necessary
to negotiate an IPSec VPN using racoon. I have a lot of
troubleshooting scenarios to cover this week, so let's carry on
where we left off.  The one configuration I purposefully left
out last time is the necessary changes to the firewall ruleset.
You might remember that we need to allow UDP port 500 for IKE
and protocol number 50 for ESP. The syntax for those rules will
depend upon whether your system is protected by ipfw, ipfilter,
or is behind another type of firewall. It will also depend upon
the order of the existing rules in your ruleset and the degree
of paranoia dictated by your security policy.  For now, create
two rules near the top of your ruleset. We may have to tweak
their placement later on when we start working with the
negotiated tunnel. Here is an example of some rules to an ipfw
ruleset:  #rules to allow