Mailinglist Archive: opensuse (929 mails)

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Re: [opensuse] Backup mailserver
On 2014-03-13 11:05, Koenraad Lelong wrote:

Like I said, the mailserver at work, and at home, has to use the ISP's
relay server. That's because outgoing port 25 is blocked in the "domain"
of the ISP. With domain I mean all IP's from the ISP's. On one side I
can understand, this limits the effects of "bots" sending from those
IP's. But for me, at this moment, it's a pain.

It is plain stupid.

The "antibot policy" is a fallacy. They do not care about stopping bots,
they want you to stop setting servers on your connection without paying
them (more).

(I know for certain that some ISPs at the beginning wanted to charge per
the number of ports you opened on your location)


In your situation, as both machines are under your control, I would
consider using some other port instead. As the idea is new to me, I
wouldn't know how to do it... transport?

[...] (reading)

Yes!

Look at the file "/etc/postfix/transport", this paragraph:


# In the case of delivery via SMTP, one may specify host-
# name:service instead of just a host:
#
# example.com smtp:bar.example:2025
#
# This directs mail for user@xxxxxxxxxxx to host bar.example
# port 2025. Instead of a numerical port a symbolic name may
# be used. Specify [] around the hostname if MX lookups must
# be disabled.


That would be on the sending side. On the receiving side something else
has to be done, too. Where?? I think that in "master.cf".

Something like:

stupid:30000 inet n - n - 10 smtpd

plus filtering or authentication, not to become a hole if they find it.


You could try use the "submission" port (587/tcp). Maybe that's the more
adequate one, and your ISP should not block that one, as it is intended
for mail clients for connecting up to external mail server, without
using smtp port.

Have a read of this doc for ideas:
file:///usr/share/doc/packages/postfix-doc/html/SOHO_README.html


(you should consider to try this setup between two local virtual
machines - so that you don't have to go go forth between one place and
the other)


--
Cheers / Saludos,

Carlos E. R.
(from 13.1 x86_64 "Bottle" at Telcontar)

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