What is NAT 

The number of available IP addresses on internet it limited. To get around this a concept of NAT (Network Address Translation) was introduced. With NAT only the router needs to have public IP address (also called Gateway, usually a DSL or Cable Modem). All devices behind NAT router have private IP addresses - usually starting with 192.168 or 10. These addresses are only valid within the router network. 

A quite common example is a simple network with one gateway (say DSL or Cable modem). The gateway has a public (WAN) IP address and does NAT. Each computer connected to this gateway gets assigned a private IP address. The gateway takes care routing the data from / to computers connected to it. To make a computer connected to gateway accessible from internet a port forwarding setting is required. If the gateway supports UPnP or NAT-PMP protocol, Air Video Server HD can transparently setup the port forwarding for the user. Otherwise manual port forwarding is required (port 45633 / TCP). 

This scenario represents a single level of NAT (just one router on network that does network address translation). Unfortunately it often isn't this simple. 

What is Double NAT 

Double NAT is a scenario where multiple routers on network are doing network address translation. Common example is a Cable or DSL modem, to which a Wi-Fi router is connected. Both modem and router have NAT enabled. Computers on the network are connected to Wi-Fi router. 

Even if port forwarding is setup on Wi-Fi router, the computer is not accessible from internet, because the WiFi router itself doesn't have public IP address. It has a private IP address within the network of DSL/Cable modem. There are multiple ways to resolve this, unfortunately none of these is a silver bullet. It depends on concrete network setup to determine which one is appropriate. 

The solution below expect the following (most common) scenario: A modem (DSL, Cable, Fiber, etc) and a Wireless router connected to the modem. 

Both the wireless router and the modem have web administration interface, each can be configured with a web browser. You might need to consult your router and modem manual to find out the IP address on which the administration interface is available. 

Possible Solutions: 

1. Setup PPPoE connection between the wireless router and modem 

This is the most robust solution, unfortunately not all ISPs provide enough information for this to be setup easily 

PPPoE can be usually setup in the wireless router's WAN settings. There are usually multiple options to configure the WAN connection of wireless router, amongst which are DHCP and PPPoE. DHCP is no good here, as it results in private IP address assigned to the WiFi router. PPPoE is better, because it bypasses the NAT in the modem, however it might need login and password information which the ISP might not provide. 

2. Put the wireless router in bridged mode 

Bridged mode on wireless router means that NAT and DHCP functions on it will be disabled. Some router call it bridged mode, some simply allow you to disable NAT and DHCP. Unfortunately some WiFi routers simply don't support bridged mode at all. 

If you manage to switch router to bridged mode, all port forwarding needs to be configured on the modem (either automatically if it supports NAT-PMP, or manually). 

3. Put the wireless router in modem's DMZ 

DMZ (demilitarized zone) is a common feature of router that allow to chose one client to which all traffic is forwarded. If your modem supports DMZ, this might be solution for you: 

1. Find out the WAN address of wireless router. For this you might need to log in to the WiFi router admin interface and look at the Status page (most router's have status pages which show relevant information about the WAN connection). 

2. Log in to the modem web administration interface, find the DMZ settings and put the WiFi router's IP WAN address there. 

Note that with this solution you will still get a double NAT warning in Air Video Server HD, but if the port forwarding on Wireless router is setup correctly, things should work. 

4. Forward the port 45633/TCP in the modem to the router 

This solution is similar to [3], except that instead of putting the WiFi router to modem's DMZ only one port is forwarded. 

1. Find out the WAN address of wireless router. For this you might need to log in to the WiFi router admin interface and look at the Status page (most router's have status pages which show relevant information about the WAN connection). 

2. Login in the modem web admin interface and configure port forwarding of port 45633 (protocol TCP) to the address from router's status page 

Note that with this solution you will still get a double NAT warning in Air Video Server. 

Still doesn't work? 

If you have configured the port manually, make sure that "Automatic Port Mapping" option in Air Video Server properties is turned off. 

Should you still have problems getting remote support working, you can contact us using email at support (a) inmethod.com . However to be able to help you, we will need as many information about your network as possible. That includes the following: 

1. Logs from Air Video Server HD. To obtain the logs, go to Air Video Server HD Preferences window and click the Create archive from Logs button. This should create a zip file with all logs and show it in Finder (OS X) or Windows Explorer (Microsoft Windows). Attach this file to support request email.

2. Screenshot of relevant router configuration and status page 

Please take the screenshot of modem's status page and router's status page. If you have configured any port forwardings, take the screenshots of port forwarding setup as well. The more screenshots the better. And you can attach the screenshots directly (or zip them), there's no need to embed them in word document.