Which IP addresses should be add to the whitelist of the mail servers?
Unfortunately the servers that are handling mail of our customers switch IP too often to keep track of them.
To only accept messages from the Spamexperts filtering servers, one need to allow emails based on hostname "delivery.antispamcloud.com". This hostname contains all active delivery IP addresses. Alternatively one can allow traffic from any IP address with the PTR record *.antispamcloud.com.
Please make sure the firewall does not block port 53 TCP.
Alternatively if allowing emails based on hostname is not an option, one could change the destination mail server to receive on an alternative port, such as port 2525 instead of the default 25 . The special port can be set for delivery when editing the destination route for the domain.
If one still want to add the Spamexperts IPs, add the IPs shown in the following Link .
For bundle account:
For users of the old bundled configuration it is possible to use the information below.
To make sure the mail-server is don't filter anything coming from our platform (since it is already filtered anyway) one can whitelist the IPs of the bundle servers.
One can also configure the mail server to accept only incoming mail connections from the range IP addresses below.
Here are all the IP addresses of the bundle Spamexperts environment.