what kind of tools can show session information(not UI ) ? ,to see packet and session monitoring?

From: rambo88 (rambo_at_lsdata.co.kr)
Date: 06/09/04

Date: Wed, 9 Jun 2004 14:23:48 +0900

I'm using linux firewall (kernel 2.4.25 )
I'd like to see and packet , bytes via session monitoring.
when I issue #cat /proc/net/ip_conntract command in console , I can't see

Where and How can I see packets , bytes via session?
or Is there a console program ( not UI ) to see session informaion include
bytes, packets ?

#cat /proc/net/ip_conntract

tcp 6 431999 ESTABLISHED src= dst= sport=1194
dport=22 src= dst= sport=22 dport=1194 [ASSURED]
tcp 6 431980 ESTABLISHED src= dst= sport=3788
dport=1863 src= dst= sport=1863 dport=3788
[ASSURED] use=1

Thanks a lot.
have a day.