Re: Dummy backup MX

[David Gibbs <david@xxxxxxxxxxxx>]

Scott Klement wrote:
> I'm not sure that I understand.  What's the purpose of ALWAYS returning 
> a soft-error?  What will you accomplish by that?

It's kind of like greylisting for the backup MX.

Normal mail servers should try the primary MX first and will, more often 
than not, connect and deliver mail.

If a normal mail server tries to connect to the backup, it will get a 
soft fail which, according to RFC, means that it's supposed to retry the 
mail delivery later.

Spammers that target backup MX's will just be told to retry ... but the 
greylisting theory states that spammers aren't interested in retrying 
(they tend to be 'fire & forget'), so they will just go away (for now at 
least).

david