Unknown network activity every 5 minutes

[McGuffey, David]

Have just started working with FC4 (after several years of working Solaris
and Windows efforts), and noticed that I'm getting network activity every 5
minutes, even when no one is logged onto the system.  It appears that a
process is waking up every 5 minutes and checking something--maybe DNS.  It
is a fresh install of FC4 desktop load, with SELinux and the firewall
enabled, and the latest updates via yum.  The machine sits behind a separate
firewall with rules that allow no externally originated connections.  It is
also on its a lone machine on its own isolated internal network, with no
connections allowed from other machines in the internal network.

Where is network activity logged?  If it isn't currently being logged, what
actions do I take to log this kind of activity?  What process might be doing
this?

Dave McGuffey
Principal Information System Security Engineer
SETA, Transformational Satellite Program
SAIC, Columbia, MD 21046
410.859.1165 (w) // 301.801.9752 (c)