[Greylist-users] OpeBSD greylisting in spamd

[Jim]

On May 27, 2004, at 10:26 AM, Bob Beck wrote:
> In short, you should Ensure that your mail server is generating 5XX
> REJECT messages, NOT sending a notification to the 'From:' or Envelope
>> From sender, as these are (almost always) spoofed in the case of spam
> and viruses. Wait until a spammer sends out several bazillion spams
> with the envelope sender set to <randomdictionaryword at yourdomain.com>
> and watch your mail server get unhappy fast as everyone sends you those
> oh-so helpful bounces.

You have a valid point, thanks for calling me on that.

Yes, I am currently accepting all messages then generating bounces 
based on the From. And yes, my queue does get heavy at times but has 
never been a problem thus far, I put together some tools to help me 
with queue maintenance when it would get heavy. I have always viewed it 
as a annoyance and something I would get to one of these days, or just 
let it take care of its self when I rebuilt this mail structure. (I had 
inherited a exchange system that was accepting message direct from the 
internet, and wanted to get rid of it in favor of a general IMAP 
server. There has just been some political issues in the way of getting 
rid of it. In the mean time, I have taken a few steps to try to protect 
it a bit, one of which was not allowing it to talk direct to the 
internet, but instead filtering all content through postfix relays.)

Thanks for pointing this out to me, as it has lit a fire under me to 
take care of this sooner rather then later.

One thought that comes to my mind, how are backup MX servers protecting 
them self from this? In general, I see many backup mx servers that just 
accept all messages addressed to domain.com then forward them on to the 
primary. Is there a standard way of protecting against this I am not 
aware of?

Thanks
Jim
jameso at elwood.net