Outgoing SMTP Servers

Ricky Beam jfbeam at gmail.com
Wed Oct 26 21:06:57 UTC 2011

On Tue, 25 Oct 2011 15:52:46 -0400, Alex Harrowell <a.harrowell at gmail.com>  
> 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.


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