Mailing List Message #12988
From: Bill Cole <>
Subject: Re: Which ports should I leave open?
Date: Sat, 10 May 2003 10:03:11 -0400
To: SIMS Discussions <>
At 4:57 PM -0500 5/9/03, Ron Johnson  imposed structure on a stream of electrons, yielding:
I think 106 is the PWD Password port, not 26

I didn't even realize that there was a 'change PWD' port for mail
servers...  I presume, then, that there's a corresponding 'change PWD' port
for FTP, etc?

No. The 'PWD' or 'poppassd' protocol is a hack that squatted on port 106 because that's where Steve Dorner of UIUC put it 15 years ago and Eudora sorta just caught on. It is a protocol with unresolvable security issues, so no one has ever had the guts to formally standardize it.

 Is there some place on the net which lists all the common
ports and what they do?

The definitive source is

A lot of related constants are defined and concepts explained at

Bill Cole

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