Re: [edlug] Backup mail server

[Andrew Aylett <andrew@xxx.xxx.xxx>]

 On 26/07/10 11:59, Brett Sheffield wrote:
> On Mon Jul 26 2010 10:12 +0100, James wrote:
> > My webhost used to offer a back-up secondary mail server, that would
> > simply store and forward email in the event that your primary email server
> > was offline. It did very basic spam checks to.
> >
> > We are setting up a email server at my job and I wandered if any company
> > offered this service? Should be an easy and cheap service to offer,
> > really.
> I'd advise against that approach.  Your backup server should have the
> same policies applied to it that your primary server does.  It needs to
> know which are real email accounts, and take the same approach on spam
> filtering, otherwise you'll end up with a load more spam.  Spammers
> regularly target the highest priority (backup) mx server as they know
> that often these are less strict on filtering and will often accept mail
> to non-existent accounts on a domain.

I'd agree with this, and add that there's a lot less need for a backup 
MX in these days of near-universal continuous service -- if your mail 
server is down, the sender will retain the mail and retry when you come 
back up, just as your backup MX would.

> And if your backup if going to have the same settings as your primary,
> why make it a backup?  Why not give both servers the same priority and
> spread the mail load?

In my case, at least, because all the mail has to go to the primary for 
delivery anyway -- just because it comes from the backup MX doesn't mean 
I won't scan it again.  I do have backup MX for a couple of my oldest 
domains (as a historical artefact) but I've not bothered setting it up 
for the dozen-or-so mail-list-related sub-domains or any newer domains.

- Andrew
-
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