How to open TCP/UDP ports on a WiFi Router for Bonjour(mDNS), AirPlay or AirPrint service

Some users may need to print through routers or firewalls, in which case they need to access the print server through these devices - the Bonjour/AirPrint port number used for TCP/IP (UDP) connections.
https://developer.apple.com/bonjour/

How to open TCP ports 5354, UDP port 5353, and TCP port 631 in the firewall on a router for Bonjour(mDNS)/AirPlay/AirPrint, you need to follow these steps:

1. Access the Router's Management Interface

First, you need to access the router's management interface. This is typically done by entering the router's IP address in a web browser. The IP address may vary depending on the brand and model of the router, but common default addresses include 192.168.0.1, 192.168.1.1, or 10.0.0.1. If you're unsure of the router's IP address, you can try these common addresses or check the "Default Gateway" next to your network connection in the Command Prompt (opened by pressing Windows key + R, typing cmd, and pressing Enter).

2. Log in to the Router

After entering the router's IP address in the browser's address bar and pressing Enter, you may be prompted to enter a username and password to log in. These credentials are usually found in the router's user manual or on a label attached to the router. If you've changed the password and forgotten it, you may need to reset the router to its factory settings to restore the default password.

3. Locate Port Forwarding Settings

Once logged in, you need to find the Port Forwarding or Virtual Servers settings. These are typically located under menus such as "Advanced Settings," "Network Settings," or "Security Settings."

4. Add Port Forwarding Rules

In the Port Forwarding settings page, you need to add a rule for each port you want to open. Here are the steps to add a rule:

• Service Name or Description: Enter a name or description for your rule, such as "TCP 5354," "UDP 5353," and "TCP 631."
• Protocol Type: Select TCP or UDP, depending on the type of port you want to open.
• External Port: Enter the port number you want to open (5354, 5353, or 631).
• Internal IP Address: Enter the IP address of the Windows computer on which you want to open the port. This can usually be found in the "Network and Sharing Center" or "Adapter Settings" on your Windows computer.
• Internal Port: Usually the same as the External Port (5354, 5353, or 631), unless you have specific requirements.

5. Save and Apply Settings

After setting up the rules, don't forget to save your changes and apply the settings for them to take effect. On some routers, you may need to click a "Save" or "Apply" button to confirm the changes.

6. Verify Port Opening

To verify that the ports have been successfully opened, you can use an online port checker tool or the netstat command in the Command Prompt to check the status of the ports. In the Command Prompt on your Windows computer, type netstat -an | find "port number" (e.g., netstat -an | find "5354") to see if the port is listening.

Notes

• Security: Opening ports can increase network security risks. Make sure you understand why you need to open these ports and only open them to trusted networks and devices.
• IP Address Changes: If your Windows computer's IP address is dynamically assigned (e.g., via DHCP), you will need to update the port forwarding rules in the router whenever the IP address changes.
• Router Brand and Model: Different brands and models of routers may have different user interfaces and configuration options. If you can't find the Port Forwarding settings, consult the router's user manual or online support documentation.

By following these steps, you should be able to successfully open TCP ports 5354, UDP port 5353, and TCP port 631 in the firewall through a router.

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What is Bonjour on my Computer? Windows 10 Bonjour Program PC Guide
https://www.freecodecamp.org/news/what-is-bonjour-on-my-computer/