SMTP Port 25 for swisscom customers blocked

I haven’t been able to send e-mails through my local mail client since today. I received an error message which guided me to this Swisscom webpage. Swisscom blocks all SMTP connections on port 25 if they don’t connect to a Swisscom mail provider like e.g. bluewin.

Swisscom has started operating an additional spam filter on the DSL network. This filter now also checks e-mail from free e-mail providers such as GMX, Google Mail and Hotmail if the e-mail is sent from a Swisscom connection … As a result of the introduction of the new spam filter, e-mail that is sent with SMTP authentication via port 25 can no longer be sent.

So I changed the SMTP port in my mail client from 25 to 587. But the server didn’t accepted the port. Thanks to rinetd a port redirection is installed in a few seconds and everything worked fine again.

So I hope spam gets less in the future and the trouble for other people (who may have more problems like me with this huge change) pays off.

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