Postfix as a backup MX

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

Postfix as a backup MX

Linda Pagillo
Hi everyone. I hope all of you are staying healthy and safe. I want to set up Postfix as a backup MX for a few of my Windows-based mail servers. I have never done this before so I have been researching to see what I could find. So far, the most complete instructions I have found are here: https://www.linuxbabe.com/mail-server/how-to-set-up-a-backup-email-server-postfix-ubuntu

Have any of you used that article to set up Postfix as a backup MX? If yes, how complete was it? If not, does anyone have different instructions that they wouldn't mind sharing with me? Thanks!
Reply | Threaded
Open this post in threaded view
|

Re: Postfix as a backup MX

Michael Ströder
On 3/29/20 4:26 AM, Linda Pagillo wrote:
> Hi everyone. I hope all of you are staying healthy and safe. I want to
> set up Postfix as a backup MX for a few of my Windows-based mail
> servers. I have never done this before so I have been researching to see
> what I could find. So far, the most complete instructions I have found
> are here:
> https://www.linuxbabe.com/mail-server/how-to-set-up-a-backup-email-server-postfix-ubuntu

The instruction given on the web page above contains screenshots of
Ubuntu-specific configuration. This might work but hides the knowledge
about all config directives needed to get it work.

In general postfix's own documentation gives you more insight, e.g. this
one:

http://www.postfix.org/STANDARD_CONFIGURATION_README.html#backup

Ciao, Michael.
Reply | Threaded
Open this post in threaded view
|

Re: Postfix as a backup MX

@lbutlr
In reply to this post by Linda Pagillo
On 28 Mar 2020, at 20:26, Linda Pagillo <[hidden email]> wrote:
> I want to set up Postfix as a backup MX for a few of my Windows-based mail servers. I have never done this before so I have been researching to see what I could find.

Reconsider.

Backup MX servers are fiddly to maintain and work best when they are configured EXACTLY like the real server, including with the exact same spam settings and backend data and blacklists and firewalls. That is a very difficult thing to do, especially if you’re on a different platform (Windows vs Ubuntu).

In general, a backup MX becomes nothing more than a server that is constantly being spammed.


--
Oh, he's just like any other man, only more so.


Reply | Threaded
Open this post in threaded view
|

Re: Postfix as a backup MX

Bob Proulx
@lbutlr wrote:
> Linda Pagillo wrote:
> > I want to set up Postfix as a backup MX for a few of my
> > Windows-based mail servers. I have never done this before so I
> > have been researching to see what I could find.
>
> Reconsider.

+1 to this.

Back in the days when systems were not directly connected and the
network was a friendlier place then relays were very useful.  But
these days with a globally connected Internet with every system being
able to directly connect to every other system there is no need for
relay systems like this anymore.

> Backup MX servers are fiddly to maintain

I would not describe them as fiddly.  But there are a few important
points that are absolutely critical.  One critical item is that the
relay_recipient_maps must be kept in sync across all of the systems.
This is a problem that is okay if handled but even better if one
avoids the need to handle it at all.  You can't break what you are not
using.

> and work best when they are configured EXACTLY like the real server,
> including with the exact same spam settings and backend data and
> blacklists and firewalls. That is a very difficult thing to do,
> especially if you're on a different platform (Windows vs Ubuntu).

Strong agreement!  For example I am not sure how one would even be
able to synchronize relay_recipient_maps *from* a Windows server.

> In general, a backup MX becomes nothing more than a server that is
> constantly being spammed.

It's definitely a target for spam.  Which must be repelled.  As
spammers routinely target lower priority MX relays expecting to find
them less well maintained than the highest priority one.

Bob