Re: What is port 3 used for?

From: Barry Margolin (barmar@genuity.net)
Date: 03/22/02

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    From: Barry Margolin <barmar@genuity.net>
Date: Fri, 22 Mar 2002 22:38:21 GMT

    In article <alanjohnmoore-6F7161.23281322032002@talia.mad.ttd.net>,
    Ajmo <alanjohnmoore@yahoo.com> wrote:
    >I've got ipchains set to block all unecessary ports, but I'm seeing some
    >connections attempts on port#3 and they appear to be coming from email
    >servers. What is port #3 used for? (all I could find was a reference to
    >"source ports") Should I open it up? and if so to who?

    RFC 1700 says it's assigned to "Compression Process", but I've never heard
    of this, so I don't think it's a commonly-used application. I've never
    heard of anything actually using port 3, so this seems very suspicious.

    If you don't have anything listening on port 3, it shouldn't make a
    difference whether you open it or not. But if you're not listening on port
    3, there's not much point in opening it.

    Are you sure it's not 113, the IDENT port? 

    -- 
Barry Margolin, barmar@genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
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