And what other tcpsump commands will be helpfull over all... I mean if you can provide me list of all commands used to check
tcpdump -v -s 0 -i any host XXX
Where XXX = IP address of your ATD. If you have multiple ATDs you can do:
tcpdump -v -s 0 -i any host XXX or host YYY or host ZZZ
Hitting "Test Connection" in your ATD will be enough to generate events if you are running the TCPDUMP command.