G-Mail Greylisting Problems

[cearnshaw]

Hello,

With messages coming from G-Mail we run into the problem that they continually fail greylisting because G-Mail has many mail servers and often does not use the same IP address when they retry the message. I do not want to whitelist all G-mail addresses, because we also receive spam from them. What would be helpful would be an option to allow the retry to pass, even if the IP is different, provided the sender's e-mail address matches each time. In the meantime, is there any work around for this short of white listing the entire domain? What we do now is wait for a complaint then white-list the one e-mail address that cannot get through, but this is not a very satisfactory solution.

Thanks,


Cameron

[m1byo]

If you have something additional to your greylisting (e.g. SPF and Baysean) then you could add the reverse lookup *.google.com (google and googlemail servers) to your greylisting safe list.

This will prevent the greylisting problem from the gmail servers, and you will still have some although reduced protection from SPF and Baysean filtering.

[rob]

Grey listing is a very effective SPAM filter and is based on a few SMTP principles that SPAM sources do not obey. However, in this particular circumstance grey listing is known to be problematic. The only real option is to white list google against grey listing, the method suggested by m1byo is a good one to ensure you get all the google servers. I should note that you will still be generally protected against SPAM/viruses that pretend to orginate from gmail (as their IP will generally not be a google domain),of course SPF will further help here.