postgrey question

Bill Moran wmoran at
Wed Jun 1 14:58:51 PDT 2005

Philip Hallstrom said:
> [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...

Postgrey ships with a whitelist of legit servers that cause problems
with greylisting.  The list is extremely short.

Keep in mind that servers that do not work well with greylisting are in
violation of the Internet mail standards.  They will never send mail

Bill Moran
Potential Technologies

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