Mail server not working with Postfix Dovecot

[iceblink]

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:
>> > Where is this machine - is it in your home or hosted somewhere? If
>> > in your home, that is not ideal. Many (most?) ISPs block common
>> > ports for incoming SMTP traffic for home customers, and a lot of
>> > mail servers out there will not accept mail from a ISP home
>> > consumer IP range. You *will* have problems getting your mail
>> > delivered. I suspect this is what you are doing, and that is part
>> > of why you are having problems.
>> 
>> This is probably different for each country. Here in the Netherlands
>> most ISP's will not block any port (at least not until they find that
>> your PC is sending spam or has an open relay mail server). The
>> biggest challenge in my country is getting a fixed IP address, or
>> failing that: keeping your DNS up to date with the changing IP
>> addresses.
> 
> That might well be. My point was that running a mail server on a
> regular home connection is not the best way to do it, and is generally
> advised against. For some ISP's it can also be considered a violation
> of terms of service.
> 
> But in this specific case the error message indicates that Google's 
> mail
> server had problems connecting, and that may very well be because the
> OP's ISP blocks that traffic. It wouldn't be surprising if they do, and
> it's the first thing the OP should now try to determine.

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.

Mind you, this only works if you use unsecured smtp, but considering 
port 25 is used, this is likely the current configuration.

(If I could, I would try it right now, but I'm at work and my workplace 
does not allow a lot of things, including telnetting via port 25.)

Best regards,
Patrick