---
title: "app-site-association.cdn-apple.com: what it is and what breaks if you block it · Kilobat"
url: "https://kilobat.app/hosts/app-site-association"
description: "app-site-association.cdn-apple.com serves Associated Domains for universal links on a Mac. What it does, and what breaks if you block it."
---

Core networking

# app-site-association.cdn-apple.com

`app-site-association.cdn-apple.com` and `app-site-association.networking.apple` serve Associated Domains. Apple says that these underpin universal links in macOS Big Sur and later.

Run by Apple · Ports: 443 TCP and UDP · Checked: 1 November 2026

## Short answer

Apple's hosts for Associated Domains, which universal links and other app-to-website links rely on.

Block with care

Blocking them can stop links from opening in their apps, and other features built on Associated Domains.

Matches

`app-site-association.cdn-apple.com` `app-site-association.networking.apple`

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 both in its Associated Domains section, for “Associated domains for universal links”, on iOS, iPadOS, macOS and visionOS.

Apple says that universal links let an app present content in place of all or part of a website.

Apple doesn't say which process on the Mac fetches the association data.

## What breaks if you block it

Block with care

Blocking them can stop links from opening in their apps, and other features built on Associated Domains.

What breaks if you block it

- Universal links may open in the browser instead of the app.
- Other features built on Associated Domains 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](https://kilobat.app/docs/blocking#protection) lists.

## Apple’s rules for its hosts

Apple’s list, [Use Apple products on enterprise networks](https://support.apple.com/en-us/101555), 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](https://kilobat.app/docs/agents#agent-network-log) for AI agents.

## Sources

- [Apple Support: Use Apple products on enterprise networks](https://support.apple.com/en-us/101555)

Checked on 1 November 2026.

## Related

- [*.cdn-apple.com](https://kilobat.app/hosts/cdn-apple-com): An Apple content delivery domain. Apple lists it for iCloud services; update and sign-in hosts sit under it too.