Re: OT? /dev/null 5.1.1 email

[David Andersen <dga+ () cs cmu edu>]

On Jul 5, 2005, at 11:28 PM, Steven M. Bellovin wrote:

> In message <Pine.WNT.4.63.0507052219510.5600@jvc>, 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