Network tracing software

[Doug Thistlethwaite <doug.t@deltanet.com>]

Hello,

Are there any network tracing packages available for Debian?  What I'm looking
for is something that will keep track of network activity and keep a log of what
connections are being made to my system (as well as where my systems are calling
out to).  I have a ISDN router that was activating itself when nobody was
talking to the internet.  After a ton of searching, I discovered that one of the
win95 PC's had Real Player G2 installed and it was calling home from time to
time...  Pretty expensive on the ole phone bill...

Thanks,

Doug