Filtering IP List

Below is an up-to-date listing of all IP ranges your filtering servers may be deployed on. For convenience, we provide the ranges in three formats to aid in entering them in your chosen firewall:

Last change to IP list: 2021-05-12

IP ranges in bold are required to correctly migrate your service to Hornetsecurity's infrastructure. Please add them as soon as possible to avoid any problems in email routing.

CIDR IP / Network mask First IP ➔ Last IP / ➔ / ➔ / ➔ / ➔ / ➔ / ➔ / ➔ / ➔ / ➔

Under M365, the IP ranges for the CIDR must be over or equal to /24. The last 2 ranges will need to be replaced with the following entries :,,,,,,,,,,,,,,,,,,,,,