Jonas Eckerman wrote:
R Lists06 wrote:
A minute or two delay from grelisting matters that much????
Greylisting usually delay a mail for more than two minutes (when it
delays, a good implementation can excempt most mail from the delay after
a while).
Even if the greylist implementation only enforces a one minute delay,
most servers will wait longer than that before retrying. 5-15 minutes
seems to be pretty common ("seems" because I havent collected any
statistics).
Just had a thought... Haven't thought it through or checked any stats
for it, so it may not be a good one.
The greylist code could be to do a reverse lookup and/or a DNS-list
check on the sending host before deciding wether it should be subjected
to the greylist or not. If it's in a dial-up-list, or the hostname fits
a pattern for dial-up and dyanamic addresses the host can be subjected
to the greylist, and otherwise it could be excempted from it.
This is sometimes referred to as selective greylisting. See for example:
http://www.tahina.priv.at/~cm/spam/
