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Where Our Certificate Checks Come From

Certificate checks run from our platform connect to your servers from the addresses below. Allow them through your firewall, and leave them out of connection rate limits, greylisting and tarpits on mail servers, so a check isn't blocked or throttled into a connection finding.

Addresses
IPv474.112.91.48, 74.112.91.49, 74.112.91.50, 74.112.91.51
IPv62600:1f10:417b:100::/62

Every check connects from one of these addresses. Not all of them are in use at any one time: the full set is listed so your allowlist keeps working as we add capacity.

Checks run by an internal agent don't use these addresses: they connect from the agent's own address inside your network.

See what our checks look like in your logs for what each check sends once it's connected.