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Re: OT? /dev/null 5.1.1 email

  • From: David Andersen
  • Date: Tue Jul 05 23:40:56 2005 
On Jul 5, 2005, at 11:28 PM, Steven M. Bellovin wrote:

In message <[email protected]>, Todd Vierling writes:

The default recommendation I give anyone these days is to use no
secondaries, and let the sender's mail server queue it up, as that's the
fastest implementation path. As a second stage, and only if the expertise
and time is available, then a backup MX with some sort of recipient
validation at SMTP time can be implemented.

The usual justification for a secondary MX is when the MX servers have
some sort of special access to the ultimate recipients -- non-SMTP mail
delivery, firewalls that they are privileged to pass, etc.
They're also mighty handy when dealing with planned, extended outages, such as moving to a new {building, ISP, etc.} or, say, losing power to the {only IX for Moscow, northeastern U.S.}, etc. It's much easier to configure your backup MXen to not toss messages or send warning emails after 4h than it is to politely ask all sending SMTP servers to do the same.

-Dave