More Intense Scanning

 # nmap -P0 -sS -O --osscan_guess -T4 -p0- -iL foocorp.ips.up -oA [file]
Interesting ports on f0-0.b1.chi.foocorp.net (216.163.143.129):
(The 65534 ports scanned but not shown below are in state: closed)
Port       State       Service
23/tcp     open        telnet
79/tcp     open        finger
Remote operating system guess: Cisco IOS 11.3 - 12.0(11)

Interesting ports on fw.chi.foocorp.com (216.163.143.130):
(The 65530 ports scanned but not shown below are in state: filtered)
Port       State       Service
264/tcp    open        bgmp
500/tcp    open        isakmp
18231/tcp  open        unknown
18232/tcp  closed      unknown
18262/tcp  closed      unknown
18264/tcp  open        unknown
Remote operating system guess: Solaris 8 early access beta through actual release
Uptime 183.426 days (since Thu Oct  3 19:22:34 2002)