Quick question:
A few years ago I had to turn off the greylisting feature of our email firewall appliance (M+Guardian), because of issues with email forwarded from our users mail.msu.edu accounts to our email system. Problem was as follows:
- mail exchange for mail.msu.edu, lets say mx01.mail.msu.edu, tries to forward message to @cvm.msu.edu
- IP address for mx01.mail.msu.edu is not in greylisting database so @cvm.msu.edu replies back with 553 temporary
- next attempt to send message from mail.msu.edu is picked up by different mail exchange, let's say mx02.mail.cvm.msu.edu
- IP address for mx02.mail.msu.edu is not in greylisting database so @cvm.msu.edu replies back with another 553
- the above cycle continues until a mail exchange that is in the greylisting database actually tries to send the message (many times with great delay) or message delivery just fails
The only solution I found to the above was to completely disable the greylisting feature on our appliance. Luckily the product we use does a great job without it, but I'd really like to enable it again and was wondering if the above is still going to cause trouble. Thanks in advance.
-Steve Bogdanski
