The IQrouter features a handy test to validate whether the WAN port of the IQrouter is reachable to computers on the public Internet. It is useful when running in a 'cascaded' (one router behind another) to validate that traffic is being forwarded or not.
Why would you want your router to be reachable? So services and applications that rely on port-forwards can work appropriately. For instance many VoIP programs like Skype rely on forwarded ports to improve the quality of the call. So whether opened automatically via UPnP or manually in the Advanced menus, port-forwards rely on the WAN of the IQrouter being 'reachable'.
What about security? The IQrouter has a good firewall that by default closes all ports and will not pass unsolicited inbound connections. But if an application needs a port to opened and forwarded to the machine it is running on, then it may try and do so via UPnP or ask the user to open it manually. The IQrouter Advanced Overview page shows the currently opened ports solicited via UPnP at the bottom of the page.
Setups that use modems that directly provide the connected router with a public IP address should always show 'reachable' by default. These are known as bridge-modems (or a modem/router combo in bridge mode). If in one of those scenarios it still shows unreachable, then the block could be happening at the ISP level. Also, we use a port in the low 1,000's, and some ISPs block low-value ports, but do allow higher numbered ports to pass, so please perform an actual test for the ports you are interested in. But note that once the test completes, the port is closed, so if UPnP had opened it, or you have a manually added port-forward, and you use the same port # for the reachability test, it will be closed.
Some ISPs (looking at you ATT uverse) force their users to use their all-in-one modem/router gateways on the line. Connecting a third-party router in a 'cascaded' scenario now requires that traffic from the ISP device be forwarded to the downstream new router. This is often called a 'DMZ' configuration or 'IP-forwarding'. We go into greater detail about this in our page about Configuring.
Finally, we want to reinforce that being Unreachable is not a problem in the vast majority of the cases, only if you have specific applications that need inbound ports open will this ever matter. So if you want to address this, then please contact the maker of your modem or your ISP on how to forward the traffic through their device.