“Arguing for an increase in your IT security budget is often an
arduous task, so many administrators turn to free open source tools
to help get the job done. But how can they rely on tools with no
commercial support and that never get past the beta version? Well,
if you think like that, you need to think again. Many open source
tools now compare favorably with commercial alternatives in terms
of features, reliability and help forums. One in particular, Nmap,
has become the tool of choice for many network and security
administrators who want to map their networks and test them for
vulnerabilities.“Nmap (Network Mapper) Security Scanner, written by Fyodor and
now up to version 4, provides a wide range of port-scanning
techniques designed to rapidly scan networks, large and small, for
network exploration and security auditing…”