AirPort - Port Mapping Basics using AirPort Utility v6.x

The following instructions provides the basics for setting up the 802.11n or 802.11ac AirPort base stations for port mapping/forwarding using AirPort Utility v6.x.

Port Mapping Setup

(Note: The port mapping setup is the same for the entire family of 802.11n & 802.11ac AirPort base stations.)

• To setup port mapping on an 802.11n AirPort Express Base Station (AXn), connect to the base station's wireless network.
• For any 802.11n or 802.11ac AirPort Extreme Base Station (AEBS) or Time Capsule (TC) you can connect to either the base station's Wi-Fi network or temporarily connect directly, using an Ethernet cable, to one of the base station's LAN (opposing arrows) ports, and then, use the AirPort Utility to make these settings:

Step #1: Reserve a DHCP-provided IP address for the host device.

(Note this is the device that you want to access from a remote location.)

1. AirPort Utility > Select the base station > Edit > Network tab. Verify that the option Router Mode = DHCP and NAT
2. Click the "+" (Add) button under DHCP Reservations.
3. Description: <enter the desired description of the host device>
4. Reserve Address By: MAC Address
5. MAC Address: <enter the MAC (what Apple calls Ethernet ID if you are using wired or AirPort ID if wireless) hardware address of the host computer>
6. IP Address: <enter the desired Private (LAN-side) IP address that you want to reserve from the DHCP pool of addresses> for the host device.
7. Click Save

Step #2: Setup Port Mapping on the base station

1. While still on the Network tab in the AirPort Utility, click the "+" (Add) button under Port Settings.
2. Description: <enter the desired description for what you are mapping
3. Public UDP Ports: <enter the appropriate UDP port value(s)> This is the WAN-side port of your AirPort's NAT service that will be "listening" for inbound UDP traffic to your local network.
4. Public TCP Ports: <enter the appropriate TCP port value(s)> This is the WAN-side port of your AirPort's NAT service that will be "listening" for inbound TCP traffic to your local network.
5. Private IP Address: <enter the reserved IP address of the host device from Step #1>
6. Private UDP Ports: <enter the same Public UDP Ports or one(s) of your choosing>
7. Private TCP Ports: <enter the same Public TCP Ports or one(s) of your choosing>
8. Click Save

The following is an example port mapping for running a web server on your local network that you want accessed from the Internet.

In this very simple example, you have a web server on your local network with a static IP address of 192.168.1.201. A remote client, using a web browser, will communicate with TCP port 80 on your AirPort's NAT "firewall" which will forward that communication to TCP port 80 on your web server. That same client will need to know your Public IP address or complete domain name of your AirPort to make the connection. The key is that you will need to have a publicly-reachable WAN-side IP address for this to work successfully. Also, you need to verify if your ISP restricts any ports. In this example, port 80 may be restricted unless you opt to subscribe to a "business-grade" level of Internet service.

(ref: "Well Known" TCP and UDP ports used by Apple software products)