Help with simple SIP set up


I have followed the Asterisk: Future of Telephony in setting up a simple SIP configuration and connecting with X-Lite softphone. This setup does not work at all. I have spent many hours trying to fix this. I installed Asterisk on Fedora Core 7, and it is up and running but I always get the 408 error on the X-Lite soft phone. I did a packet capture and it displays as such:

116 3.636208 SIP SIP: Request: REGISTER sip: SIP/2.0

117 3.638209 ICMP ICMP: Destination Unreachable Message,

No idea why it is doing that. I can ping my computer form the server and vice versa. I did an Ethereal capture on the server and it said the same thing, except it said the SIP had a bogus length. I cannot find any resolution to fix this. I am doubting the validity of the simple SIP setup as described in the Asterisk book, but maybe it is right. Anyway, if someone could point me in the right direction with this, I would GREATLY appreciate it.

Nevermind, I found the issue: iptables was blocking the traffic. Be sure to turn IPTables off if possible!