[lug] [ot] MX backup partners

[Jeff Schroeder]

Dave asked:

> > There are a significant number of mail servers that will bounce
> > after 1 day, though 4 days is much more common.
>
> How many?  How do you know?

In my experience, 1 day is very much the exception.  E-mail is actually 
quite robust, and the 4- or 7-day expiration most servers use is 
intended precisely for the case you're talking about: a receiving 
server goes down for a few hours (or-- shudder-- a day or two).  By 
waiting a couple of days until giving up, a sending server can lower 
the number of bounce messages to its users.

That being said, the expiration is something that can be configured on 
the server... so it's entirely possible that someone who's either very 
hasty or very confident of the servers would set it to a single day.  
But I suspect it's very much the minority.

$0.02,
Jeff