[geeks] ADMINISTRIVIA: Changes to mail delivery policies

[Jonathan C. Patschke]

> Sure, if your connection is down for more than a "normal" amount of
> time....  but in that case you probably want to move your MX, not just
> set up a secondary MX that'll hide all your e-mail in its queue for the
> duration....

You're confusing the optimal solution with a workable solution.  My MX is
staying right here, in my house, for the most practical of reasons.  I
-like- having my mail queued remotely and then streaming in.  It means
that the queues mail comes in a single flood, rather than in trickles from
hundreds of places at once.

> > Even when I worked at $ISP, we had -two- second-tier MXes.  We're in
> > Texas.  Our second-tier MXes were in Ohio and California.  You can only
> > imagine how nice this was when $Datacenter lost power for several hours
> > due to a UPS failure or when $Upstream forgot that we existed, and
> > decommissioned our IP address space.
> 
> No, I can't quite imagine.  Even if you/they owned and operated those
> machines and had full control over them there's not much point to
> landing all your e-mail in Ohio and then having to pull it down to
> Texas again.  Why not just leave it where it belongs -- in the
> sender's queue?

Because lusers who see DSNs have this stupid habit of resending mail
(since they've long-forgotten how to read) or placing support calls, or
(worse) calling the person they were trying to mail, and saying that we've
gone offline.  Queuing the mail elsewhere hides the failure, and saved us
from luser backlash.

Also, there are some broken MTAs (Exchange comes to mind) that does -not-
perform exponential backoff.  It just retries on regular intervals.  If it
gets a 400-series error instead of a 500-series error, it retries
-immediately-.  Rather than having to deal with -more- broken crap when
the mail server goes to hell, it just gets silently queued elsewhere.

> Your configuration takes that control out of her hands, and maybe even
> out of your own hands, causing her mail to have to sit in some remote
> mailer's queue for an even more undefined period of time, often with
> no indication of where it is or why it hasn't been delivered yet.

If the secondary MX is properly configured, this is a non-issue.  Mail
will come flooding in within an hour.

> > Load balancing is -not- the only reason to have a secondary MX.
> 
> If, and _ONLY_ if you directly control the MTA on the secondary MX host.

Or if it is controlled by someone with sufficient clue.  Setting up a
secondary MX with identical spam rules, who's only output rule is "route
all mail to --> here, when that server comes up" is trivial.

> That's pure and utter BS.  Even in the early days of the Internet there
> was no real reason to need a secondary MX.

Or secondary nameservers, or redundant anythings, I'm sure.  It's all just
a big capitalist scam.

I sincerely apologize for having not kept my mouth shut in the first
place.  IHBT.  HTH.  HAND.

--Jonathan