nanog mailing list archives

Re: Outgoing SMTP Servers


From: "Ricky Beam" <jfbeam () gmail com>
Date: Wed, 26 Oct 2011 17:06:57 -0400

On Tue, 25 Oct 2011 15:52:46 -0400, Alex Harrowell <a.harrowell () gmail com> wrote:>
Why do they do that?

You'd have to ask them. Or more accurately, you'd need to ask their system integrator -- I've never seen an "in house" network run like that. (and for the record, they were charging for that shitty network access.)

Bottom line: Blocking port 25 (smtp) is undesirable, but necessary for a modern consumer internet. (Translation: It f'ing works.) This is the ISP saying, "You aren't a mail *server*." MUA's (mail clients) should only be connecting to specified MSA's or MTA's (mail *servers*). They should never be connecting to random MTA's (presumably for direct delivery, which is the job of an MTA not MUA.) The only people who can effectively police this is the ISP. Individual mail server admins and RBL maintainers can only guess and be reactionary, which is often wrong, still lets spam through, and becomes stale rather quickly.

--Ricky


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