[107530] in North American Network Operators' Group
Re: ingress SMTP
daemon@ATHENA.MIT.EDU (Mark Foster)
Fri Sep 5 05:12:18 2008
Date: Fri, 5 Sep 2008 21:12:03 +1200 (NZST)
From: Mark Foster <blakjak@blakjak.net>
To: Mikael Abrahamsson <swmike@swm.pp.se>
In-Reply-To: <alpine.DEB.1.10.0809051032010.29587@uplift.swm.pp.se>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On Fri, 5 Sep 2008, Mikael Abrahamsson wrote:
> On Fri, 5 Sep 2008, Simon Waters wrote:
>
>> If the ISP blocks port 25, then the ISP is taking responsibility for
>> delivering all email sent by a user, and they have to start applying rate
>> limits.
>
> MUAs should stop sending email via 25 and use 587 or equivalent instead.
> There is little actual reason why someone should be able to send TCP/25 SMTP
> email from a residential connection when most software support authenticated
> TCP/587 submits.
>
> We don't allow most of our residential customer base to speak SMTP TCP/25 to
> anywhere at all (and we have millions of them). Wish more ISPs would do the
> same.
>
Probably fair enough, if you as an ISP can get away with enforcing this
sort of policy then so much the better.
However relaying through your own ISPs 25/tcp should surely then make it
relatively easy for noise to be tracked down and nailed at the source - by
ISPs? (Do abuse@ desks investigate spam these days?)
