[Techtalk] Postfix HELO controls

[Maria McKinley]

Has anyone ever run into problems using postfix helo controls to reject 
spam? I'm thinking of implementing the rejection of mails that 
identifies itself as our machine or our ip. I'm a little confused as to 
how it determines what is our machine vs. what is just identifying 
itself as our machine, but it looks like this part is at least straight 
forward to implement.

 From what I have read, it sounds like faking to be the recipient's 
machine is a thing that is common for spammers to do, but virtually 
unheard of for legitimate mail servers. I assume this is because they 
are trying to protect their own ip/machine name from being blacklisted. 
If so, this sounds like an obvious thing to do, but wanted to check with 
you experts to see if there are some problems with this implementation I 
am overlooking.

cheers,
maria