postgrey question

[Philip Hallstrom]

[description of postgrey snipped]

> The main advantage of this is that spammers and viruses have massive amount 
> of email lists and just try to send it to as many people as possible. They 
> are not going to wait and try to send the e-mail again, thus you effectively 
> block many amount of spam and virus e-mail before it's even being processed 
> by amavis / clamav / spamassasin, saving up system resources.

This is also the problem with greylisting... some services only attempt to 
send the email once and if it fails, give up completely.  I don't remember 
if postgrey comes with a whitelist of IP addresses or not, but I do 
remember seeing a list that included things such as Southwest Airlines 
ticket confirmations and some amazon stuff.

Anyway, that's something to watch out for if it's relevant for you...