--- title: "What is this host? Apple and app servers your Mac connects to · Kilobat" url: "https://kilobat.app/hosts" description: "54 hosts a Mac connects to, from gateway.icloud.com to swcdn.apple.com: who runs each, what it serves, and what breaks if you block it." --- What is this host? # The servers your Mac talks to, explained. 54 hosts and host patterns you see in a firewall prompt, a DNS log or Kilobat’s Connections tab: who runs each one, what it serves, which processes use it and what breaks if you block it. Also see the [processes behind them](https://kilobat.app/processes). Search hosts ## Sync and cloud storage - [*.apple-cloudkit.com](https://kilobat.app/hosts/apple-cloudkit-com): Apple's CloudKit service. Apps sync their iCloud data through it, and Apple lists api.apple-cloudkit.com for app notarization on macOS. - [*.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. - [dropbox.com](https://kilobat.app/hosts/dropbox-com): Dropbox's official domains for its product, API and static content. - [*.dropboxusercontent.com](https://kilobat.app/hosts/dropboxusercontent-com): A Dropbox domain on its list of verified domains, with hosts such as dl.dropboxusercontent.com. - [gateway.icloud.com](https://kilobat.app/hosts/gateway-icloud-com): Apple's CloudKit gateway. Apple lists it for CloudKit content, including XProtect malware definitions and Voice Control assets. - [*.icloud-content.com](https://kilobat.app/hosts/icloud-content-com): An Apple domain for iCloud services. Large uploads and downloads of iCloud content, such as files and photos, can go to hosts under it. - [*.icloud.com](https://kilobat.app/hosts/icloud-com): Apple's iCloud domain. Apple lists *.icloud.com for iCloud services; specific hosts under it have their own pages. - [onedrive.live.com](https://kilobat.app/hosts/onedrive-live-com): Hosts that Microsoft lists for consumer OneDrive, for file storage and the OneDrive service. ## Updates and downloads - [*.apps.apple.com](https://kilobat.app/hosts/apps-apple-com): Apple's store content host, for apps, books and music, next to *.itunes.apple.com. - [audiocontentdownload.apple.com](https://kilobat.app/hosts/audiocontentdownload-apple-com): Apple's host for GarageBand downloadable content. - [configuration.apple.com](https://kilobat.app/hosts/configuration-apple-com): The Apple host that Apple lists for Rosetta 2 updates on macOS. - [download.developer.apple.com](https://kilobat.app/hosts/download-developer-apple-com): Apple's hosts for Xcode's downloadable components. - [gdmf.apple.com](https://kilobat.app/hosts/gdmf-apple-com): Apple's software update catalog host. Device management services also ask it which updates are available. - [gs.apple.com](https://kilobat.app/hosts/gs-apple-com): An Apple host that devices need during setup and for operating system updates. Apple lists it in both sections of its host list. - [*.itunes.apple.com](https://kilobat.app/hosts/itunes-apple-com): Apple's store content host, for apps, books and music. - [lcdn-locator.apple.com](https://kilobat.app/hosts/lcdn-locator-apple-com): Apple's Content Caching locator, which devices ask to find a caching Mac on their network. - [lcdn-registration.apple.com](https://kilobat.app/hosts/lcdn-registration-apple-com): Apple's hosts that a Content Caching Mac uses to register, get its configuration and report. - [mesu.apple.com](https://kilobat.app/hosts/mesu-apple-com): Apple's host for software update catalogs, the lists of updates that devices check against. - [*.mzstatic.com](https://kilobat.app/hosts/mzstatic-com): An Apple domain for store content such as apps, books and music, and apps from websites and alternative marketplaces. - [osrecovery.apple.com](https://kilobat.app/hosts/osrecovery-apple-com): Apple's hosts for macOS Recovery, used when you reinstall macOS over the internet. - [swcdn.apple.com](https://kilobat.app/hosts/swcdn-apple-com): Apple's host for macOS update downloads. Big transfers from it are macOS updates. - [swdist.apple.com](https://kilobat.app/hosts/swdist-apple-com): An Apple host for macOS updates, listed in Apple's software update section. - [swdownload.apple.com](https://kilobat.app/hosts/swdownload-apple-com): An Apple host for macOS update downloads. Apple says that it works through proxies. - [swscan.apple.com](https://kilobat.app/hosts/swscan-apple-com): An Apple host for macOS updates, listed in Apple's software update section. - [sylvan.apple.com](https://kilobat.app/hosts/sylvan-apple-com): Apple's host for Aerial screen savers and wallpapers on tvOS and macOS. - [updates.cdn-apple.com](https://kilobat.app/hosts/updates-cdn-apple-com): Apple's hosts for software update downloads, over HTTPS and plain HTTP, for all Apple platforms. - [xp.apple.com](https://kilobat.app/hosts/xp-apple-com): An Apple host that Apple lists in the software update section of its host list, without saying what it does. ## Core networking - [*.aaplimg.com](https://kilobat.app/hosts/aaplimg-com): An Apple domain behind Apple's content delivery. Many apple.com hosts resolve to names under it, so connections show up with it. - [app-site-association.cdn-apple.com](https://kilobat.app/hosts/app-site-association): Apple's hosts for Associated Domains, which universal links and other app-to-website links rely on. - [*.apple-dns.net](https://kilobat.app/hosts/apple-dns-net): Apple's domain for the DNS of iCloud services. iCloud hosts resolve through names under it. - [captive.apple.com](https://kilobat.app/hosts/captive-apple-com): Apple's internet connectivity check for networks with sign-in pages (captive portals). Kilobat uses it too. - [doh.dns.apple.com](https://kilobat.app/hosts/doh-dns-apple-com): Apple's DNS over HTTPS (DoH) host. Apple lists it for encrypted DNS resolution in macOS Big Sur and later. - [mask-api.icloud.com](https://kilobat.app/hosts/mask-api-icloud-com): An iCloud Private Relay host on TCP 443. Unlike the relay hosts, Apple says that it supports proxies. - [mask.icloud.com](https://kilobat.app/hosts/mask-icloud-com): The iCloud Private Relay hosts. With Private Relay on, Safari browsing and DNS lookups go through them. - [probe.icloud.com](https://kilobat.app/hosts/probe-icloud-com): Apple's iCloud connection testing hosts. - [time.apple.com](https://kilobat.app/hosts/time-apple-com): Apple's time servers. Macs use NTP on UDP port 123 to set their date and time from them. ## Security and accounts - [account.apple.com](https://kilobat.app/hosts/account-apple-com): Apple's hosts for Apple Account authentication in Settings and System Settings. - [albert.apple.com](https://kilobat.app/hosts/albert-apple-com): Apple's device activation host, needed during setup and when installing, updating or restoring the operating system. - [crl.apple.com](https://kilobat.app/hosts/crl-apple-com): Apple's hosts for certificate revocation lists and certificates, used to validate the certificates of Apple's services. - [idmsa.apple.com](https://kilobat.app/hosts/idmsa-apple-com): Apple's Apple Account authentication hosts. Signing in to iCloud, the App Store and Xcode needs them. - [ocsp.apple.com](https://kilobat.app/hosts/ocsp-apple-com): Apple's certificate status (OCSP) servers. The Mac asks them whether an Apple-issued certificate has been revoked. - [ocsp.digicert.com](https://kilobat.app/hosts/digicert-ocsp): DigiCert's certificate status and revocation list hosts. Apple lists them because some of its services use DigiCert certificates. - [token.safebrowsing.apple](https://kilobat.app/hosts/token-safebrowsing-apple): The Apple host for Safari's fraudulent website warnings. - [valid.apple.com](https://kilobat.app/hosts/valid-apple-com): An Apple certificate validation host. Apple lists it for every platform, on port 443, with proxy support. ## Apple services - [apple-relay.apple.com](https://kilobat.app/hosts/apple-relay-apple-com): The Apple host that Apple lists for Apple Intelligence Extensions. - [apple-relay.cloudflare.com](https://kilobat.app/hosts/private-cloud-compute-relays): Hosts on Cloudflare and Fastly that Apple lists for Private Cloud Compute, where some Apple Intelligence requests are processed. - [guzzoni.apple.com](https://kilobat.app/hosts/guzzoni-apple-com): Apple's host for Siri and dictation requests. - [*.push.apple.com](https://kilobat.app/hosts/push-apple-com): The Apple Push Notification service (APNs). The Mac keeps one connection to it, so notifications, iMessage, FaceTime calls and iCloud changes can arrive. - [*.smoot.apple.com](https://kilobat.app/hosts/smoot-apple-com): Apple's search services, for suggestions in Siri, Spotlight, Look Up, Safari, News, Messages and Music. ## Diagnostics, analytics and ads - [diagassets.apple.com](https://kilobat.app/hosts/diagassets-apple-com): The Apple host that devices use for diagnostics that help detect possible hardware issues. - [metrics.icloud.com](https://kilobat.app/hosts/metrics-icloud-com): Apple's host for iCloud device diagnostics. ## Apps and helpers - [dl.google.com](https://kilobat.app/hosts/dl-google-com): Google's download host, where Chrome gets its updates. - [registry.npmjs.org](https://kilobat.app/hosts/registry-npmjs-org): The npm public registry, where npm downloads JavaScript packages by default. - [*.zoom.us](https://kilobat.app/hosts/zoom-us): Zoom's domains for all Zoom clients, over TCP 80 and 443 and UDP 443. To find which app opened a connection, use Kilobat’s Connections tab or the [agent network log](https://kilobat.app/docs/agents#agent-network-log). Checked on 1 November 2026.