[Mimedefang] DNS Lookups in MD - Was RBL and DNS lookups

[Jeff Rife]

On 12 May 2007 at 11:04, Les Mikesell wrote:

> > Why would you restrict it this way?  If someone is bouncing and they 
> > don't have a valid MX, then you never sent them mail anyway, and it's a 
> > spoof.  So, *anything* without a valid MX should be tossed.
> 
> A bounce doesn't necessarily come from an address where you sent the
> mail - it can come from somewhere after forwarding.

Well, I guess I wasn't thinking, anyway, because it depends on what you 
look up here.  If you do the MX lookup on '<>', then of course there 
isn't really a valid MX, but if you are trying to figure out who is 
really sending you the e-mail (parsing "From:" and such), then I would 
think that you could reject anyway even if the envelope sender is '<>'.

This is one of those cases where it would be nice if there were an RFC 
for the format of bounce e-mail so you could easily parse it to see if 
it really is a bounce to a message you sent out.


--
Jeff Rife | "I'm mad as hell, and I'm not going 
          |  to take pan & scan anymore."