Help with Chicken of the VNC and Airport

Is your 802.11n AirPort Extreme Base Station (AEBSn) the only router in your network configuration and is connected directly to the Internet modem?

If so, and your VNC server is behind the AEBSn on the local network, you will have to configure the AEBSn to map port 5900 to the VNC server.

Is this what you need help setting up?

The basic steps to configure for VNC are as follows:

o Configure the machine you want to control (VNC Server) to allow VNC access. If the VNC Server is behind a router, then this would entail at least three things: 1) Configure the OS X Firewall to allow VNC access, 2) Configure the router to map port 5900 to the VNC Server, and 3) Know the WAN IP address of your router. (Note: One way to get the WAN IP is to go to the web site http://whatismyip.com and make a note of the ip address.)

o Connect to your VNC Server from a VNC Client from the Internet.

And I tried to do port forwarding but it doesn't seem to work.

Let's double-check your port mapping settings.

1. Reserve a DHCP-provided IP address for the VNC Server.
Internet > DHCP tab
o On the DHCP tab, click the "+" (Add) button to enter DHCP Reservations.
o Description: <enter the desired description of the host device>
o Reserve address by: MAC Address
o Click Continue.
o MAC Address: <enter the MAC (what Apple calls Ethernet ID if you are using wired or AirPort ID if wireless) hardware address of the VNC Server>
o IPv4 Address: <enter the desired IP address>
o Click Done.

2. Setup Port Mapping on the AEBSn.
Advanced > Port Mapping tab
o Click the "+" (Add) button
o Service: <you can ignore this setting>
o Public UDP Port(s): 5900
o Public TCP Port(s): 5900
o Private IP Address: <enter the IP address of the VNC Server from the above step>
o Private UDP Port(s): 5900
o Private TCP Port(s): 5900
o Click "Continue"

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

These are instructions for using AirPort Utility in Manual Setup.

For example "Internet > DHCP tab" would be, AirPort Utility > Manual Setup > Internet (icon) > DHCP tab. Sorry for any confusion.

I read that NAT cannot be used when there is an older computer to be communicated with.

Not true.

NAT is a service that allows your router to share a single IP address to multiple clients on its local network. If you disable NAT, then all ports are open on the router. This is typical when you reconfigure the router as a bridge. Note that port mapping/forwarding only works if NAT is enabled.

If your AEBSn is the only router connected to the modem then it should have NAT enabled ... and why you would need to configure it for port mapping to allow VNC communication to a VNC Server behind it. You only should need to open port 5900 for this communication.

Ok, I think it would be best if we start from the beginning.

The VNC Server is the computer you are going to want to access from the Internet. Where will this computer reside: home, office, somewhere else? Regardless of where, what is the network configuration at this location? An example network configuration would be: Cable Modem > Router > computer. What is the make/model of each of those devices that you are using?

On the other hand, the VNC Client is the computer that you will use to access the VNC Server. Same questions as for the VNC Server: Location, Network configuration & component make/model?

The following is an example that I have used in the past and works:

I have a Mac Mini at home that I want to connect to from the Internet. This is my VNC Server. It is not running any special VNC software, but instead, is using OS X's Apple Remote Desktop feature to make it a VNC Server. It is connected to an 802.11n AirPort Extreme Base Station (AEBSn). Which, in turn, is directly connected to a Motorola SB5101 modem. Using the AirPort Utility, I configured the Mac Mini to have a DHCP-reserved IP address and mapped port 5900 to this address.

I also have a MacBook and while visiting my local coffee shop, I want to access the Mac Mini. This MacBook is the VNC Client. It will be running the VNC of the Sea client software. I connect to the coffee shop's wireless network to gain access to the Internet, and then, I run the VNC Client on the MacBook; enter the WAN IP address of my home's router, and then, connect to the Mac Mini using the VNC Client software.