Hi there,

Just to elaborate a bit for you.

NMAP is a nice port scanner, that will tell you what ports are open on your firewall. Its a good start for any scan on a host.

Nessus (better then SATAN) is more a vulnerability scanner on the actual services. Don't get me wrong, Nessus picks up open ports and all, but not as extensively as what NMAP will. Nessus is more for telling you why those ports are bad for being open.

Finally, I always finish off with a Langaurd Network Scan. Its a Doze based scanner, but it is highly effictive. I have often found that NMAP will find ports that LanGaurd will not, and Vice Versa. Making them a team is often the most thorough way of scanning a host.

Anyway,
Just thought your might enjoy the info.