> > I'm looking for recommendations for an Intrusion Detection system for my > > firewall. Preferably a debian package but not restricted to. > > Try aide http://packages.debian.org/unstable/admin/aide.html. aide or tripwire will both do host based intrusion detection. if you want network intrusion detection try snort. there is a debian package and there are lots of pre-written rules to detect attacks on snorts web site. it's also being very actively developed. adam.