Security and accounts

crl.apple.com

crl.apple.com serves Apple's certificate revocation lists (CRLs), and certs.apple.com serves certificates. Apple lists both for certificate validation on every platform.

Run by ApplePorts: 80 TCP (crl), 80 and 443 TCP (certs)Checked: 1 November 2026

Short answer

Apple's hosts for certificate revocation lists and certificates, used to validate the certificates of Apple's services.

Don’t block

Don't block them. The Mac can't fetch Apple's revocation lists or certificates, and Apple services can fail validation.

Matches
crl.apple.com certs.apple.com

A name with *. covers every name under it: *.push.apple.com matches 1-courier.push.apple.com.

What it serves

Apple's enterprise host list names crl.apple.com on port 80 and certs.apple.com on ports 80 and 443, both for “Certificate validation”.

The ocspd man page says that macOS fetches certificate revocation lists from the network and caches them in /private/var/db/crls.

On a Mac, trustd evaluates certificates and uses that cache.

Processes that use it

trustdPart of macOS. It checks certificates for every app, and asks certificate authorities whether a certificate was revoked. Its connections are small.Process →

What breaks if you block it

Don’t block

Don't block them. The Mac can't fetch Apple's revocation lists or certificates, and Apple services can fail validation.

What breaks if you block it

  • Revoked Apple-issued certificates may not be detected.
  • Certificate validation for Apple's services may fail.

With Kilobat Pro and the network filter, you can block a host for every app or for one app: in Connections, select a connection and choose Block. Apple’s own services are never blocked by Kilobat’s Protection lists.

Notes

CRLs are signed by the certificate authority, so serving them over plain HTTP doesn't let anyone change them.

Apple’s rules for its hosts

Apple’s list, Use Apple products on enterprise networks, says that devices open these connections, not Apple’s servers. Apple services fail any connection that uses HTTPS interception, so a proxy that inspects TLS should leave Apple’s hosts alone.

If a firewall allows hosts by name, allowing *.apple.com covers most Apple services, Apple says. A firewall that works only with addresses can allow 17.0.0.0/8 for IPv4, and 2403:300::/32, 2620:149::/32 and 2a01:b740::/32 for IPv6.

To see which app on your Mac opened a connection to this host, use Kilobat’s Connections tab, or the agent network log for AI agents.

Sources

Checked on 1 November 2026.