Identifying open ports

[Rick Stevens]

Kenneth Porter wrote:
> --On Monday, June 14, 2004 12:06 PM -0600 "Rodolfo J. Paiz" 
> <rpaiz at simpaticus.com> wrote:
> 
>> If you do something like "netstat -leanp | grep 80" you should see
>> whether Apache is listening on that port or not. However, the firewall
>> may still be blocking that port; check your iptables configuration to
>> make sure.
> 
> 
> I usually use "lsof -i -n" (list open files, IP ports only, numeric (no 
> DNS lookups)), but one must be root to use this. As with netstat, pipe 
> the result through grep to identify specific ports.

I prefer nmap or nmapfe against the public IP of a machine.  If you've
been trojaned or rootkitted, lsof and netstat are suspect.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-                   To err is human, to moo bovine.                  -
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