sofia allows you to enable siptrace from the cli<br><a href="http://wiki.freeswitch.org/wiki/Sofia#Debugging_Sofia-SIP">http://wiki.freeswitch.org/wiki/Sofia#Debugging_Sofia-SIP</a><br><br>Or external tools like tcpdump/ngrep etc can be used<br>

<a href="http://wiki.freeswitch.org/wiki/Packet_Capture">http://wiki.freeswitch.org/wiki/Packet_Capture</a><br>