Speeding Your Scans -- Firewalled Hosts

An example using slightly older version of Nmap and no -T:

 # /usr/bin/nmap -P0 www.insecure.org
Starting nmap V. 3.15BETA2 ( www.insecure.org/nmap/ )
Interesting ports on www.insecure.org (64.71.184.53):
(The 1600 ports scanned but not shown below are in state: filtered)
Port       State       Service
22/tcp     open        ssh
25/tcp     open        smtp
53/tcp     open        domain
80/tcp     open        http
113/tcp    closed      auth
8080/tcp   closed      http-proxy
Nmap run completed -- 1 IP address (1 host up) scanned in 556.479 seconds