Mail server not working with Postfix Dovecot

[Patrick Asselman]

> On 07 Dec 2015, at 17:17, Mariano Jara Melagrani <mjaramelagrani at gmail.com> wrote:
> 
> On 07/12/15 11:42, iceblink wrote:
>> On 2015-12-07 14:11, Petter Adsen wrote:
>>> On Mon, 07 Dec 2015 11:29:15 +0100
>>> iceblink <iceblink at seti.nl> wrote:
>>> 
>>>> On 2015-12-07 08:42, Petter Adsen wrote:
> <snip>
>> An easy way to find out might be to telnet from an outside PC into the
>> home server.
>> Something like:
>> 
>> telnet home.server 25
>> HELO <hostname>
>> 
>> If you get an answer from your home server then the ISP is not blocking.
> 
> I'm at home right now, but I'll try that as soon as I get the chance.

Tried it just now, no connection is ever established on port 25:

$ telnet 181.230.43.12 25
Trying 181.230.43.12...
^C
$

whereas port 465 is open but refusing connections:

$ telnet 181.230.43.12 465
Trying 181.230.43.12...
telnet: connect to address 181.230.43.12: Connection refused
telnet: Unable to connect to remote host
$

> 
>> Mind you, this only works if you use unsecured smtp, but considering
>> port 25 is used, this is likely the current configuration.
> 
> How can I know if I'm using unsecured smtp?

It depends on your configuration.
Your postfix configuration should have statements like
smtpd_use_tls=yes
smtpd_tls_security_level = encrypt
smtpd_tls_auth_only = yes
I’m not a postfix expert, but if you share your /etc/postfix/main.cf with us, someone here can figure it out. (make sure to edit out anything you don’t want to be public).

Reading some other posts in this thread, it looks like you configured a secure connection and are probably enforcing it, otherwise I can’t explain why port 25 is not answering and port 465 is answering (unless your ISP is blocking port 25, that might still be an option).

Anyway if you fix the certificate issue you should be able to connect via port 465.


Best regards,
Patrick