RE: [cobalt-users] Strange sendmail reports -- email attack?

[flash22@xxxxxxx]

On Sun, 22 Apr 2001, Brian M. Rahill wrote:

> Colin,
> 
> >How about blocking mail from gia.net completely and see what happens????
> >It's at least a starting point if nothing else and cannot possibly break
> >anything.
> 
> Yep.  That took care of it...  Thanks.    Pretty stupid not to have tried 
> that first, eh?!!
> 
> Block the mail....WOW...what a novel concept!
> 
> Light dawns on marble head.  Better days are ahead...

ahh...at least it's a compliant mail server....the 451 reply for
unresolvable domain name is a 'temporary error' so the other server is
justified in retrying again...when you block it you are sending  550 error
back which more or less says 'i's never gonna work, give up' 
Unfortunatly i find some spam sources using servers don't seem to get
that idea....(They tend to annoy me to the point of actually doing
something about them ;)

ps: it's not necessarily stupid to have let it try for a while, it could
have been just a transient nameserver error on a reasonable email...

otoh i find lots of open relays from emails that are causing those kinds
of errors ;)

gsh