Question

Which IP addresses should I whitelist on my mail servers to accept filtered incoming mail traffic from SpamExperts?

Answer

That depends on solution you use.
1. Public domain cloud
2. Bundled-solution

SpamExperts public cloud (per domain filters)

In order to accept messages from the SpamExperts public cloud (antispamcloud.com) filtering servers, emails coming from "delivery.antispamcloud.com" host should be explicitly allowed on your mail server. This hostname contains all active IP addresses used to send email from SpamExperts public cloud. Alternatively it is possible to allow traffic from any IP address with the PTR record *.antispamcloud.com.

Please make sure your firewall rules do not block port 53.

In case if allowing emails based on hostname is not an option it is possible to configure destination mail server to receive emails on alternative port, such as for instance port 2525 instead of the default 25. If you want to configure non-default port for mail delivery on your destination server it can be configured via destination route for the domain in Openprovider control panel (e.g. like mail.mydomain.com:2525). 

If neither approach above is acceptable SpamExperts public cloud IPs could be explicitly whitelisted. Full list of IPs of SpamExperts public cloud is available via link.

SpamExperts cloud hosted by Openprovider (bundles)

For customers who use SpamExperts bundles in Openprovider the list of IPs is different from the SpamExperts public cloud. 

In order to accept incoming mails from Openprovider SpamExperts hosted environment, the next IP addresses needs to be allowed on the destination mail server.