Greylisting...

[mikea]

On Mon, Sep 25, 2006 at 07:58:38PM +0200, Gordon Colyn wrote:
> Please can you give me more info on how to do this?
 
in response to my post containing 

> An additional sendmail ruleset stops SMTP transactions with MTAs that
> HELO/EHLO as our MX, with this message:
>           "ruleset=check_rcpt, arg1=<recipient_address>, 
> relay=[relay_IPADDR],
>            reject=554 5.7.1 Invalid helo rejected; send mail to 
> abuse at odot.org
>            if rejected in error - are you really 192.149.244.25"
> which stops even more _and_ gives me nice patterns to watch in my maillog
> database. But all that's off-topic here, so ask in private mail if you
> want more info.

For Rob Poe, Gordon Colyn, and everyone else who asked how to do 
rejection on HELO/EHLO string: 

http://mikea.ath.cx/areyoureally.html

should give you the pointers you need. It's very brown'n'serve, though 
you will want to set the list of rejected HELO/EHLO strings to your needs

*and*

you will want to tailor the rejection message to your standards. 

-- 
Mike Andrews 
mikea at mikea.ath.cx, mandrews at odot.org
Information Security
Oklahoma Department of Transportation