On 07/01/2014 04:00 PM, motty cruz wrote:
yes I guest I could change the variable delay, I will do a quick search
to see how would affect users. some users are very sensitive to this
issues.
What mail server and version of it are you using?
There was a good suggestion made about postscreen, earlier, if you are
using version 2.8 or later of postfix, IIRC.
I was a bit confused about what greylisting means, until a few days ago.
Basically, your server maintains a database of servers that it has
previously talked to and received legitimate emails from.
If it has not talked to a server at this ip before (generally a block of
256 or so addresses) then it says "Hey, I'd love to accept your incoming
mail, but I'm *really* busy right now. Could you come back in 5 minutes
and I'll be able to take it then?
Normal mail servers will come back. Spam servers do a sort of wham, bam,
thank you ma'am version of sending mail. Except that they don't even
bother to say "thank you", and they certainly don't come back in 5
minutes. They just move on to their next victim. They don't waste time
with slow receiving servers.
The problem is that saying "come back in 5 minutes" does not mean that
even legitimate servers are going to come back in 5 minutes. They might
wait 10 minutes. Or 15. Or 20. Or 30. Or an hour.
Some of the sites listed in postgrey's default whitelist file delay as
much as 12 hours between reties. And you cannot necessarily trust
whitelists to cover all the important senders on an ongoing basis.
-Steve
