[linux-elitists] Offsite services (MX / DNS)

Marc MERLIN marc@merlins.org
Fri Nov 15 23:08:04 PST 2002


On Wed, Nov 13, 2002 at 08:15:11PM -0500, Jeremy McLeod wrote:
> That's assuming you have more than one machine, or you have an
> arrangement with another person/organization to provide backup MX
> services for your domain(s).  Not everyone has that luxury.

MX probably not, but secondary DNS is easy to get.
Contrary to what  some think, secondary DNS is useful  even if you don't
have an offsite  MX. The reason is that if you  don't have secondary DNS
and your  primary MX/DNS  drops off  the internet,  mail for  you starts
bouncing due to host unknown => you lose mail.
If you  have an  offsite DNS server,  mail for you  gets spooled  by the
senders, and  they'll try to resend  it to you for  several days, giving
you the  time to fix your  connection or setup another  MX elsewhere and
repoint your domain entries to another IP if needed.

On Thu, Nov 14, 2002 at 11:10:25AM -0800, Aaron T Porter wrote:
> 	Oh, please. This *is* the internet -- I've never met the guys that
> do run my MX and DNS secondaries face to face. Hop on to IRC or a mailing
> list and find someone who'd be willing to swap service with you, or shell
> out the money for a hosted service -- it's not that pricy, especailly
> compared with lost mail, IMO.

Unfortunately, I don't trust anyone to be secondary MX anymore. The odds
of  them fucking  up their  mail config  and bouncing  my mail  are much
higher than me dropping off the net for more than 5 days.

Also, because of my spamassassin and teergrubing setup
( http://marc.merlins.org/linux/exim/sa.html ), as well as my SMTP callbacks,
I issue a lot of temporary rejects that would cause all the spam to clog my
secondary MX because I would never accept it :-)

On Thu, Nov 14, 2002 at 03:18:04PM -0500, Jeremy McLeod wrote:
> I agree.  The context, however, was that backup DNS service is useless
> if you don't also have backups for your other services.  That's pretty
> irrefutable.  I think Dan's a jackass for announcing that backup DNS is

Well, hopefully you see that it's not true now. For mail, secondary DNS
is vital, even if you don't have an offsite MX.

Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking 
Home page: http://marc.merlins.org/   |   Finger marc_f@merlins.org for PGP key



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