On Mon, Jun 24, 2013 at 12:57:12PM -0700, Scott Vanderbilt wrote:
> On 6/24/2013 12:18 PM, Eric Faurot wrote:
>
> >>I've also tried various options using 'relay backup' without
> >>success. The man page does not give an example for backup servers.
> >>So, I'm not sure how to proceed.
> >
> >"relay backup" is used to setup secondary mail servers for a domain,
> >that is a server that accept mails for a domain and relay to MXs with
> >higher priority (i.e. lower preference in DNS).
> >
> So when you specify 'mx' as a parameter for the 'backup' keyword,
> what does that mean precisely? A DNS server host name? A preference
> value?
>
> When I see MX, I think of the MX records in the DNS zone file. I
> tried using a preference value, and that was rejected by smtpd as
> invalid.
>
If the backup parameter is specified, the current server
will act as a backup server for the target domain.
Accepted mails are only relayed through servers with a
lower preference value in the MX record for the domain
than the one specified in mx. [...]
therefore:
accept for domain foobar.org relay backup mx2.example.org
will turn your machine as a backup mx for domain foobar.org with the
same priority as mx2.example.org, only relaying to other MXs that have
a higher priority
--
Gilles Chehade
https://www.poolp.org @poolpOrg
