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I have setup postfix to use dovecot for authenticating smtp requests. This worked well until yesterday. Now my mail client says the server is offline and telnet for all standard ports yields: Connection Refused. I can send email from the webmail and can connect to the ports with telnet from within the server.

/var/log/mail.log says nothing about this refused connection.

Any ideas on how to get to the bottom of this problem?

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up vote 0 down vote accepted

Seems my ISP has blocked the standard smtp port (25) and my postfix was only running on that port. Changed everything to smtps (port 465) and now it works.

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Don't use SMTPS; it has been deprecated for a decade now. – adaptr Jan 29 '13 at 10:46
So what is the alternative? And does it change anything apart from the port number? – Nicholas Feb 1 '13 at 21:16
Use STARTTLS with SASL instead, as amply documented in RFC4409. – adaptr Feb 4 '13 at 8:27
I will have a look at that. Thanks! – Nicholas Feb 4 '13 at 11:54

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