RE: transport nexthop nexthop

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transport nexthop nexthop
\ Gary W. Smith (15 Jan 2008)
. \ (Wietse Venema) (15 Jan 2008)
. . \ Gary W. Smith (15 Jan 2008)
. \ Victor Duchovni (15 Jan 2008)

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Subject:	RE: transport nexthop nexthop
Group:	Postfix-users
From:	Gary W. Smith
Date:	15 Jan 2008

Wietse,

Sorry for top posting.

I went with the private MX route. Seems to work fine for what we need to do (and still give us flexibility).

Thanks,

Gary Wayne smith

________________________________

From: owner-postfix-users on behalf of Wietse Venema
Sent: Tue 1/15/2008 3:53 AM
To: Postfix users
Subject: Re: transport nexthop nexthop

Gary W. Smith:
> Hello,
>
> We're using transport from a backup MX server to send email to the
> primary MX via transport. Recently the primary location encountered a
> significant outage that left it without reliable internet connection for
> over a week (that it on the main lines -- 5 T1's all through different
> providers all through one line carrier). Luckily we were able to get
> one line back up and finally route some mail.
>
> What we would like to do is keep the backup MX server using the
> transport table and if that transport if offline to use a secondary IP
> as a backup. In theory we could setup the slower line at the primary
> location as a backup MX as well but we really don't want the excess
> traffic unless we really need it, so basically it will be running an
> unadvertised SMTP service.
>
> Is there a simple way to do this in postfix. I looked at
> fallback_transport and configured our test domain for this but when I
> stopped traffic from the backup to the primary (via an iptables drop
> rule for all traffic to mx1.domain.tld) it didn't fail over to the
> fallback.

As DOCUMENTED Postfix won't use the fall-back feature when it is
MX host because too many people lost mail due to loops between
Postfix and fall-back.

There currently is no automatic solution for alternate paths from
secondary MX to primary, except listing the primary in a private
DNS zone with different preferences for the fast and slow paths.

Wietse

> Here is what I have in main.cf
> transport_maps = hash:/etc/postfix/transport
> fallback_transport = hash:/etc/postfix/transport-fallback
>
> /etc/postfix/transport
> domain.tld smtp:[mx1.domain.tld]:25
>
> /etc/postfix/transport
> domain.tld smtp:[an_ip_address]:25
>
> Any help would be greatly appreciated.
>
> Gary Wayne Smith
>
>
>
>