[NTLUG:Discuss] Blood from a firewall

[brian@pongonova.net]

Is there any way, a trick perhaps, to get an external firewall to give
up its WAN address?  I'd like to have my Linux box "phone home" and
send new DHCP assignments I get from my ISP to a remote e-mail
address, but the problem is figuring out a way to retrieve the new
address from the firewall.  I'm sure I could concoct something out of
wget and connect to the firewall via HTTP, but I'm looking for simple
here.  I thought maybe traceroute might help, but the firewall
effectively masks its WAN address.

Or am I looking for blood from a turnip here?

  --Brian