The following table lists URLs and ports that should be opened on your firewall for Malwarebytes on Windows devices to communicate properly with these servers. By default, these ports are open, but if you have customized your firewall verify the following rules are in place.
| URL | Purpose |
| www.malwarebytes.com:443 | Used to verify connectivity to the Malwarebytes servers. |
| cleo.mb-internal.com:443 | Used by the in-app purchase flow to simplify the process of upgrading or renewing your Malwarebytes Premium subscription. |
| links.malwarebytes.com:443 | Used by the in-app purchase flow to simplify the process of upgrading or renewing your Malwarebytes Premium subscription. |
| iris.mwbsys.com:443 | Used for serving in-app messaging, such as news about the latest threats, personalized reports, renewal reminders or other offers. |
| my-device.malwarebytes.com:443 | Used to register your installation with Malwarebytes My Account portal, my.malwarebytes.com. |
| cdn.mwbsys.com:443 | Used to deliver new updates and downloads to the Malwarebytes product. |
| sirius.mwbsys.com:443 | Used to check for updates for both the product version and the protection database. |
| keystone.mwbsys.com:443 |
Used to validate your Malwarebytes Premium subscription. |
| telemetry.malwarebytes.com:443 |
Communicates telemetry and threat information to Malwarebytes servers. More information on our telemetry can be found on our Privacy Policy. |
| hubble.mb-cosmos.com:443 |
Used to validate threats against Malwarebytes Nebula servers for better protection and to reduce potential for detection of legitimate applications. |