[aklug] Re: Postconf review

From: Kevin Miller <atftb2@alaska.net>
Date: Tue Sep 22 2015 - 20:49:20 AKDT

On 09/22/2015 08:17 PM, Royce Williams wrote:
> I can't really speak to the Postfix config, but I can clarify the DNS
> a bit more.
>
> As Kevin noted, your current PTR record for 74.220.215.66 is
> host266.hostmonster.com. If it's easy to change (or have Hostmonster
> change) your PTR to be mail.tj49.com, that would work well.
>
> But if your current PTR record can't be changed, you can change your
> MX record instead, so that it points to host266.hostmonster.com
> directly.
>
> Both methods bring forward and reverse DNS into alignment. Ideally
> (and even aesthetically :) ), having that hostname reflect the
> expected mail flows' domain would be better -- but not strictly
> required.

MX records are just for inbound mail. The sending server just needs to
be able to to resolve some name to an IP. The sending side doesn't care
much if they match or not. You want your forward and reverse records
aligned for when *you're* sending (outbound) mail. When sending, it
doesn't matter to my server what you call yourself - the name just has
to be resolvable and listening on port 25. But if you *send* to my
server your ducks need to be in a row.

But that said, you should look into SPF and DKIM for your server, as
they help validate it when it sends. And invalidate servers run by
punters spoofing your users and/or domain...

...Kevin

-- 
Kevin Miller - http://www.alaska.net/~atftb
Juneau, Alaska
In a recent survey, 7 out of 10 hard drives preferred Linux
Registered Linux User No: 307357, http://linuxcounter.net
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Received on Tue Sep 22 20:49:48 2015

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