I got my mother an android smartphone for her birthday. One of the great apps I like is the IP Webcam. I've experimented it successfully on my own network at home. By way of port forwarding, I can use a web browser from anywhere in the world to view what the smartphone is seeing. The typical application is home security/surveilance. But for me, being able to see whatever my mother sees at her home 180 miles away would be instrumental in helping her solve daily problems.
Unfortunately, what worked for my set up didn't work on hers. Same phone, same router, and the same ISP, but somehow I just couldn't make port forwarding work in her home. I couldn't even access her router remotely even though such feature was enabled for her router. Finally, I found the culprit -- she had an Ooma Hub (for VoIP telephony) placed between the cable modem and the wifi router. This is the default setup for Ooma and works for perhaps 95% of the users, except for the 5% who run network servers from their home networks. The Ooma Hub had either blocked incoming ports and/or masked the external IP address (http://canyouseeme.org showed a complete different external IP addresses with and without the Ooma Hub). I am not quite sure. The bottom line is that it would not work with the default recommended setup.
Some suggested designating the local IP address of the wifi router as the DMZ in the Ooma configuration. But there have been complaints that it didn't work, so I didn't bother trying it, even though I didn't get to the bottom of it.
I took the other approach -- placing the Ooma hub behind the wifi router. I made it to work. Since I couldn't find this documented anywhere else, I am hereby doucmenting the solution that works for me.
- Access the Ooma Hub's configuration page at http://setup.ooma.com
- Change its Network Connection setting from Automatic to Static IP Address.
- Assign the Ooma Hub a static local IP address outside of your wifi router's DHCP pool, say 192.168.1.101, assuming your router's DHCP IP pool ranges from 192.168.1.2 through 192.168.1.100.
- Assign your router's IP address as Ooma Hub's static DNS Server and Router (gateway) addresses.
- Make sure you click "Update" after you've made the above changes.
- Access your router's configuration page, and specify the Ooma Hub's new static local IP address (e.g. 192.168.1.101) as the virtual DMZ host. Make sure DMZ is enable and the changes are applied.
- Power down both the Ooma Hub and the router.
- Reverse the current physical connections so that the the cable modem connects directly to the router's uplink socket, and the Ooma Hub's "Modem" socket connects to one of the router's available LAN sockets.
- Connect one additional cable from the Ooma Hub's "Home" socket to one of the router's available LAN sockets.
- Power up the router and wait for it to reach steady state.
- Power up the Ooma Hub and wait for the blue light.
- That should do it.
- To access the Ooma Hub's configuration page, you'd now have to use the static local IP address (e.g. http://192.168.1.101 in our running example) instead of http://setup.ooma.com . If you have a more advanced router, you would be able to fix this problem by adding translation. But personally I'd rather not do that and keep the changes minimum in case I need to restore the orignal set up in the future.