IDS options: Signature databases and heuristics  The following
is the first tip in a two-part series on intrusion detection
system (IDS) techniques. Part one below outlines basic IDS
solution features. Part two will spotlight three types of IDS
tools, and the pros and cons of using each.  Intrusion detection
systems (IDS) have become more popular and necessary as
administrators realize that firewalls alone aren't enough to
keep a network perimeter secure. While a firewall closes all
unused ports, it can not secure ports that are intentionally
left open to meet the operational requirements of an
organization. For example, a company may leave open TCP Port 80
so HTTP traffic can reach the Web server. But how can it then
protect against the countless HTTP-based exploits that exist?
This is where an IDS comes in.  Basically, an IDS does for
network traffic what an antivirus program does for the file
system. Here I'll make comparisons between the two types of
solutions, explaining how each comb networks for malici