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?)