Re: [exim] Exim server behind NAT router (and HELO)

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Author: Jeremy Harris
Date:  
To: exim-users @ exim. org
Subject: Re: [exim] Exim server behind NAT router (and HELO)
Toralf Lund wrote:
> kmb wrote:
>> Yes there is a correct way to configure a MTA behind a NAT router and a
>> Dynamic IP address setup... Please use an Upstream Smart host.
>>
> I've considered that. However, isn't there also an HELO/EHLO involved
> when the local MTA passes on data to the smart host, and shouldn't that
> be valid, too?


Strictly, yes. However, smarthosts and their clients are really
operating outside the design boundaries of SMTP and as such can
use more lax rules by arrangement. That is, you need to ask
the operator of your smarthost what they'll accept.

> Something else I've been wondering about is if the smarthost may be
> dynamically configured, too. Like, can I tell exim to always use the
> official MX for the current domain? (I'm looking for a setup that works
> without modifications when you e.g. move the PC between your ISP at home
> and the LAN at the work.)


Exim is flexible enough, certainly. "A simple matter of programming".

Cheers,
    Jeremy