[horde] [SOLVED] Error connecting to smtp server
jmozdzen at nde.ag
Mon Sep 2 15:18:36 UTC 2013
Zitat von Michael M Slusarz <slusarz at horde.org>:
> Quoting "Jens-U. Mozdzen" <jmozdzen at nde.ag>:
>> Zitat von Michael M Slusarz <slusarz at horde.org>:
>>> [...] Further, everyone should be using authentication to the
>>> SMTP server. The days of sending via open SMTP relays (should
>>> have) long since passed.
>> not within corporate setups. Identifying local systems by IP is
>> often considered sufficient (and I wouldn't disagree).
To be clearer: I'm referencing the "The days of sending via open SMTP
relays..." above. STD 72 isn't as widely adopted as some do wish, at
least not in it's new definition of the submission port.
> You are incorrect. This exact usage is defined for MSA's in the
> RFC. See, e.g. RFC 6409 [4.3]:
> "...unless it has already independently established authentication
> or authorization (such as being within a protected subnetwork)."
> You should never ever ever ever ever insert mail into the message
> delivery stream via port 25.
I agree that one "should" use port 587 to better distinguish between
MSA and MTA, but practice shows that port 25 is still used a lot for
that, especially in corporate setups with strongly controlled internal
networks. Maybe that's why its use is covered by section 3.1 of RFC
6409: "A site MAY choose to use port 25 for message submission by
designating some hosts to be MSAs and others to be MTAs."
De facto, many corporate environment have been using MSAs (without
calling them MSA) since implementing SMTP-based email so many years
ago... setting up an internal MSA (accepting submissions based on IP
address or some different authentication scheme) and using a separate
MTA infrastructure for, well, mail transport. Many just have not
switched to using the new port - but as said above, they're covered by
STD 72 / RFC 6409...
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