Backup Mail Server Questions

Bill Moran wmoran at
Mon Sep 27 06:07:51 PDT 2004

"Toomas Aas" <toomas.aas at> wrote:

> > From:          Bill Moran <wmoran at>
> > First off, what does setting up backup DNS/mail gain the end user?  Unless
> > you have mirrors on radically different networks, of things like WWW and
> > mail, backup DNS doesn't really accomplish anything.  If the net
> > connection goes down, you're offline anyway, so who cares if DNS still
> > works?
> This is only true if your DNS server is behind the same network 
> connection with your other services. We recently had a situation where 
> one of our mail sub-domains and one pretty important web application 
> were out of operation FOR A MONTH because the external contractor who 
> handles DNS for this sub-domain had "forgotten" their DNS server into 
> another network and it was disconnected. Until they sorted out the 
> mess, from the end-users POV things basically didn't work, even though 
> the mail and web servers themselves were fine.

We're not disagreeing.  My comment says "unless your on different networks".

If you WWW, mail, and DNS are all the same server (like the current setup, for example)  backup DNS gains nothing.

The simple fact is that not _everyone_ needs a backup DNS and backup
MX.  The sysadmin needs to honestly assess the situation and make an
informed decision.

The reason I fight so hard _against_ it is because folks like are marketing so hard FOR it, even when people don't
need it.  And provides lousy service.  Additionally,
many registrars won't register your domain unless you have at least
2 DNS servers, which is a stupid requirement.  And many DNS/SMTP
validation services will consider a single DNS or a single SMTP
server and error, which is not always true.

Bill Moran
Potential Technologies

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