NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/protocol/tcpip/5618

Internet Message Format | 1992-12-15 | 1.9 KB

Path: sparky!uunet!gatech!usenet.ins.cwru.edu!slc6!trier
From: [e-mail] (Stephen C. Trier)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Port Allocation.
Date: 15 Dec 1992 15:53:39 GMT
Organization: Case Western Reserve University, Cleveland OH (USA)
Lines: 27
Message-ID: <[e-mail]>
References: <avalon.724431555@coombs>
NNTP-Posting-Host: slc6.ins.cwru.edu

In article <avalon.724431555@coombs> [e-mail] (Darren Reed) writes:
>When allocating ports for program use, it is commonly recognized that
>under 1024 is priveledged as per the latest numbers RFC.

Check RFC 1122 on "privileged" ports: No ports are "privileged", except by
convention of some OS's.  This convention can NOT be assumed to exist outside
of that particular OS.  The only difference about ports under 1024 is that
they are used for well-known ports and therefore, non-RFC protocols should
probably not use ports in that range.  (BTW, when 1122 was written, there
were only 256 well-known ports.  The argument still applies, though.)

All the specs say now are that ports under 1024 are to be used for well-known
ports.  Ports above 1024 are technically a free-for-all, though individual
operating systems may choose to allocate them in whatever arbitrary way they
like.  BSD does so, in an admittedly arbitrary way.

The NCSA telnet allocations you saw were fine.  The telnet I use here starts
with local port 65534 and works its way down to 1024, then wraps around to
65534 again.  The wrap around could be at 1 were it not for some design
compromises (read: bugs) in the way it handles multiple connections on the
same local port.

--
Stephen Trier                      "We want to offer you a price that you
Network software type               just can't afford to take advantage of."
Case Western Reserve University         - Sales blurb from HSC Software
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