Grey List - Spam Filtering

[charlesindia]

I have enabled Grey List - Spam Filtering and added the following in Safe List
google.com
*.google.com
But still the mail sent from gmail is not delivered immediately.
When I check the log the host name for gmail server looks like mail-893-jkd8.google.com
How to add this in Safe List.

[Code Crafters]

There are several options for IP listings including grey list safe IPs. In your situation you would need to tick the option for "IP of Host / Domain" with a domain of "mail-893-jkd8.google.com". Note that this option looks up the IP so it needs a full domain specified and can't use wildcards (like *). You can also do a Reverse DNS lookup for "*.google.com" which does allow asterisk (*) wildcards. I'd recommend adding both of these.

[charlesindia]

Hi Chris,
Thanks for your update, As you mentioned, I cannot add mail-893-jkd8.google.com as google has thousands of mail host and it changes frequently.
I will try for the second option you suggested.

[Code Crafters]

The second option for reverse DNS lookup is what's meant to be used in this situation. It takes the IP and looks up the PTR record to turn the IP back into a meaningful domain and then compares this using wildcards (*s).