Alright, let's break down why your intranet.domain.com (port 80) isn't loading from another device, even though Central Administration on port 12548 works. Since you’ve got the basics covered (local access, DNS pointing correctly), here are the most likely fixes to check step by step:

• Verify Windows Firewall Rules
  The fact that port 12548 works means most network routing is fine, but port 80 might not be allowed through the firewall on your SharePoint server. On the server:

  1. Open Windows Defender Firewall > Advanced Settings.
  2. Navigate to Inbound Rules and look for rules allowing HTTP (port 80).
  3. Ensure the rule is enabled for Domain/Private networks, and that it allows traffic from remote devices (either all IPs or your client device’s IP range). If no rule exists, create a new one to allow TCP port 80.

• Check IIS Site Bindings
  Your frontend site might not be bound to the correct URL or IP in IIS:

  1. Open IIS Manager on the SharePoint server.
  2. Locate your frontend web application, right-click > Edit Bindings.
  3. Confirm there’s an HTTP binding for intranet.domain.com on port 80. The IP address should be set to All Unassigned or the server’s network-facing IP (not just localhost).

• Validate SharePoint Alternate Access Mappings (AAM)
  SharePoint relies on AAM to recognize and respond to external URLs. If intranet.domain.com isn’t listed here, it’ll reject requests:

  1. Open Central Administration > System Settings > Configure alternate access mappings.
  2. Select your frontend web application from the dropdown.
  3. Ensure intranet.domain.com is added to one of the public URL zones (like the Intranet zone). If not, click Add Internal URLs to add it.

• Test Port 80 Connectivity from the Client
  Rule out network-level blockages by testing port 80 directly from the remote device:

  • On Windows, open Command Prompt and run:
    Test-NetConnection intranet.domain.com -Port 80
  • If the test fails (shows "TcpTestSucceeded: False"), the issue is definitely network-related (firewall, router settings, etc.). If it succeeds, move to browser/SharePoint permission checks.

• Check Client Browser Settings
  Sometimes client-side settings get in the way:

  • Clear your browser cache and try accessing the site in incognito/private mode.
  • If using Windows Authentication, ensure intranet.domain.com is added to your browser’s Trusted Sites list (in IE/Edge, go to Internet Options > Security > Trusted Sites > Sites).
  • Verify the client device isn’t using a proxy server that blocks access to your intranet domain.

• Confirm Web Application Permissions
  If the site requires authentication:

  • Ensure the user account you’re using from the remote device has permissions to access the frontend site.
  • If you’re using anonymous access, check that the web application is configured to allow anonymous users (Central Administration > Application Management > Manage web applications > select your site > Authentication Providers > enable anonymous access).

Start with the firewall and IIS bindings first—those are the most common culprits when one port works and another doesn’t. If you hit a snag with any of these steps, feel free to share more details and we can dig deeper!

内容的提问来源于stack exchange，提问作者Hennie Francis