Wireshark is a real good GUI packet capture and analysis tool. I have a portable version on a thumbdrive that I occasionally use to diagnose problems on AIX servers.
First, capture the data with iptrace. Refer to the iptrace man page for options. For example, to capture rsh (port 514) from hosta and write it to /tmp run:
startsrc -s iptrace -a "-s hosta -p 514 /tmp/hosta.out"
After your done capturing your data, run:
stopsrc –s iptrace
Then download the output file to your desktop and open the resulting file with Wireshark. Wireshark will automatically determine that the file is from AIX iptrace.