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Greylisting has been great for many years but times have changed and the current settings that I can see in ORF don't cut it anymore. Let me know if there is a change I can do, I had to disable it. started using banks of IP ranges outside the /24 subnet any companies on there email system is getting greylisted and never getting sent as they hop around on the /16 subnet.

I think 2 options could be added to the greylisting. An exception to greylisting based on HELO or add a checkbox for "Accept delivery retries from the same /16 subnet".

Gmail is starting to take this route as well.

by jean.davis 2 years ago

Hello jean.davis,

Thank you for the suggestion. However, Microsoft already sends emails from /14 and /15 blocks as well, so the "accept delivery retries from the same /16 subnet" option could turn out to be a temporary fix only. As for the "HELO exception" list, the FQDN submitted in the HELO command may or may not contain the domain of the service provider (e.g. *, *, * as the customers can - and often do - replace it with a hostname that contains their own domain instead. So unfortunately this would not help much either.

Your best bet is to exclude the IP ranges of the outbound MXs of the problematic mail service providers using the "IP Exception" list of the Greylisting test. The relevant IP ranges can be obtained by querying the SPF record of the problematic sender. OR, you can get an up-to-date (and ready-to-import) IP exception list via the URL below.

To import it into ORF, just follow the steps below:

1. Save the GL_IP_Exceptions.txt file to any folder
2. Start the ORF Administration Tool
3. Select File > Import > Greylisting > IP exception list…
4. Browse the saved .txt file and click OK
5. If you see the prompt “Do you want to overwrite the current list with the imported”, select “No”
6. Click OK, save the ORFconfiguration (Ctrl + S) and you are done.

I hope this helps :)

by Daniel Novak (Vamsoft) 2 years ago

@Daniel Novak (Vamsoft): That will help thank you.

Is there plans for this to update automatically. :)

by jean.davis 2 years ago
(in reply to this post)


@jean.davis: We may build this into the Greylisting test in the future, but in the meantime I will update the list in every few weeks. Feel free to send us an email to if you cannot access the file for some reason.

by Daniel Novak (Vamsoft) 2 years ago
(in reply to this post)


@Daniel Novak (Vamsoft): Got the file and imported. Using it now.

by Jean 2 years ago
(in reply to this post)


@Daniel Novak (Vamsoft): Is this list updated? I wasn't sure if you were still updating or just a snapshot from 2 years ago.


by jean.davis 1 month ago
(in reply to this post)


@jean.davis: Hello Jean,

No, that list has not been updated. Send and email to please, and I will send you the most recent one.

by Daniel Novak (Vamsoft) 1 month ago
(in reply to this post)

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