postgrey question

Bart Silverstrim bsilver at
Thu Jun 2 04:54:44 PDT 2005

On Jun 1, 2005, at 5:35 PM, Philip Hallstrom wrote:

> [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...

I'd guess those are broken email systems that I wouldn't WANT email 
from, personally.  I mean...what happens if you get something from 
those people and your mail server goes down for an hour, or is unable 
to accept mail for a window of time?  From the remote's viewpoint, 
greylisting should just be another way of saying it needs to try again 
in the next interval.

If people keep accepting broken implementation as the status quo, we're 
going to keep getting people who leave broken implementations in place.

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