techlist06: > I'm working on converting to using postscreen. Studying the details. I > have a question from the docs related to the delays due to the effective > greylisting caused by "Tests after the 220 SMTP server greeting". I believe > my server would qualify as a small site receiving mail for just a few > hundred users. > > Snippet from the Howto: > " The following measures may help to avoid email delays: Small sites: > Configure postscreen(8) to listen on multiple IP addresses, published in DNS > as different IP addresses for the same MX hostname or for different MX > hostnames. This avoids mail delivery delays with clients that reconnect > immediately from the same IP address.
Note, this recommendation applies to clients that reconnect from the same IP address. > Can someone help me understand why this helps? The postscreen temporary whitelist is by client IP address. > If I add an IP to the server and configure it as a second instance > of the MX hostname, how does that help with a server that may > reconnect from a different IP? Note, the above recommendation applies to clients that reconnect from above recommendation does not apply. > I though tthat if it > reconnected immediately from the same IP, that would be a good thing. Or > maybe I misunderstood "immediately". I took it to mean immediately after > getting a 4xx response and drop. I assume this doesn't do anything to help > with servers like Google that will connect from a different server? Note, the abive recommendation applies to clients that reconnect from the same IP address. If still applies when different servers share the same external (NAT) IP address. Wietse