[H-GEN] I was sittin' and wondering'

[Robert Brockway]

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On Mon, 4 Nov 2002, [iso-8859-1] Andrew M wrote:

>  --- Robert Brockway <robert at timetraveller.org> wrote:
> > [1] Actually there is nothing wrong with having multiple primary MXs
> > in a peered arrangement.  Humbug itself used to do this, and may again
> > one day.
>
> May I ask why Humbug used to have multiple MXs; doesnt now, and may have
> multiple MXs in the future? Just curious. (And want to learn more.)

Hi Andrew.  We do have multiple MXs:

avon:~>host -t MX humbug.org.au
humbug.org.au mail is handled by 100 mailhub1.uq.net.au.
humbug.org.au mail is handled by 100 mailhub2.uq.net.au.
humbug.org.au mail is handled by 200 postoffice.telstra.net.
humbug.org.au mail is handled by 50 caliburn.humbug.org.au.

I was noting we don't have multiple _primary_ MXs anymore.  A primary MX
is a shorthand way of referring to the MX (mail exchange server) with the
lowest number ascribed to it.  When delivering mail a sending MTA (mail
transport agent) will attempt to deliver to the lowest numbered MX.  If
this fails it will try the next highest, etc, until it either succeeds or
runs out of MXs for the domain.

We used to have two MTAs with the same MX level, hence they were both
referred to as primary.  Each one was capable of delivering Humbug's mail
independently of the other.  So in those days if caliburn went down
zerlargal could keep delivering mail indefinately.  Or vice versa if
zerlargal went down but caliburn was ok.  In contrast, if caliburn goes
down now (as happened a few weeks ago), mail to humbug.org.au will be
queued on one of our backup MXs but won't proceed to delivery until
caliburn is back up and in a position to process the mail.

So why do we only have one primary MX now when we used to have two?  A
certain ISP in Brisbane that was housing zerlargal (for free) went into
administration and vaporised almost overnight, leaving us with one box to
run the lists & web.  It all happened so fast even the staff at this ISP
were left with their mouths open.

At some point in the future Humbug may again acquire a 2nd spot to house a
server.  Who knows :)

Cheers,
	-Rob

-- Robert Brockway B.Sc. email: robert at timetraveller.org  ICQ: 104781119
   Linux counter project ID #16440 (http://counter.li.org)
   "The earth is but one country and mankind its citizens" -Baha'u'llah


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