I understand how the greylisting works, but I have found customers complaining that Gmail emails appear to be delivered only after several hours.

Trawling through the logs I can see different Gmail IP's getting greylisted all the time and my suspicion is that once SF greylists a Gmail IP, then Gmail try to send the email from a different IP, which also gets greylisted...then Gmail try from yet another IP, which gets greylisted....  and round in circles we go.

 

Does anyone have any ideas on this??

 

I have looked at Gmail's SPF record, but they seem to have about 8 blocks of /18, /19 & /20 subnets. This adds up to about 65,000 IP's and I don't want to add all these into the greylistallow file....any suggestions?

 

Cheers