port forwarding

A recurring frustration on the technology front is when I eventually figure a solution, implement it, and 2 years later need to make a change and have completely forgotten the solution and have to figure it all out again.  So I will use my site as reference material for future time savings.

I have 2 houses and they both have cameras connected to DVRs.  When I am in the house I can access the DVR, both live recording and past recordings, by connecting a monitor to the DVR and operating the DVR controls or, since the DVR is connected by cable to my network, I can access the DVR from my desktop or even my smart phone.  The problem is when I want to access the cameras away from the house, what I will call remote access vs. local access.

Both houses connect to the internet using DSL and the DSL companies, which are different, have provided modems (one a Zyxel the other an Actiontec) which are connected to the DSL/telephone line. I have connected a router, in both cases Netgear Genie N150, to the modems.  The Netgear router allows wireless connection such as with a laptop or smartphone, and cable connections as with my security system and the DVR to which the cameras are attached.  All work fine and I have elsewhere described how my security system interfaces with the internet and alerts me when there is an issue.  The problem is when I wish to access my cameras remotely.

The modems provided by the DSL companies are more than modems, they are also routers, though for clarity I will call them modems.  So between my DVR and the outside world are two routers the Netgear and the DSL modems.  And the Netgear routers and DSL modems have firewalls to prevent external intrusion and when I am on the outside trying to access the DVR in the network, I am an external intruder and am blocked.  So how can I bypass the security of the routers.

There are several ways to do this – UPNP (you plug and you play) is apparently the easiest tho I have not used it because one of my DVR’s is not compliant.  My solution is to configure the router to port forwarding which means allowing or forwarding a port or throughway on the DVR to the outside world.  Port forwarding is easily configured on the Netgear router but what to do with the modem.  A couple years ago when I figured all this out, I think I configured the Zyxel modem to a DMZ (demilitarized zone) mode which means the modem was demilitarized or rendered powerless to external intrusions which could slip past the modem and reach the router which had a firewall in place, except for the port to the DVR to which it allowed access.

6 months ago all worked fine, and then I installed a new modem at the Atlanta house – a new version of Zyxel, and I couldn’t access the Atlanta cameras.  You would think that I would have quickly connected the lack of camera access with the arrival of the new modem but even this took me some time to figure out.   And then, when I realized it was the  modem, my first problem was just accessing the Zyxel modem.  I know its address ( because it is the gateway to the internet and you get the gateway address by going to the run box (win key +R) then type “cmd” then type “ipconfig”.  But I got no connection when I entered the address in the browser address bar on my laptop.  So I connected the laptop directly to the modem thinking the intervening router was the problem, and still got no connection.  On inspiration I rebooted (switched on and off) the modem and, success, the Zyxel login page with a prefilled password appeared.  I had the option to enter a new password or login with the prefilled password.  Sensing I was on a roll I logged in with the existing password.  Mistake – I got a status page but nothing else.  So, more research, reboot the modem and this time I entered a new password and success, I got the works and the first question I was asked is do you want to change the modem from routing mode to bridging mode.  “Bridging mode” what was that?  Some more research indicated that the modem acts simply as a bridge when in bridging mode,  like a conduit, which is what I wanted.  So I selected bridging mode which was confirmed and then hooked the router to the modem.  And.  No internet connection.  This probably meant that the router had to be configured.  But now the internet was down and I was getting complaints, so I thought enough progress for today, I will switch the modem back to routing mode, and when I have done my research on how to configure the router I will come back and switch them both to bridging mode.  But.  Even with the modem now in routing mode and all changes undone, still no internet connection.  Drat.

Time to call the DSL provider.  The technician was very helpful.  He said first let’s get the internet connection back.  Again connect the laptop to the modem.  The modem did not respond to cues from the laptop.  So I did a hard modem reset with a paperclip pushed against the reset button until all the lights went out.  Then waited for the modem lights to return then got the providers’ website where I entered my internet details and had the internet connection restored, then got the Zyxel site where I checked the modem was in routing mode, then connected the router to the modem and the laptop to the router and I was back to internet access as before.  The technician really knew his way around and said he would now help me configure the modem and router to bridging mode.  So I instructed the modem to go to bridging mode and we turned our attention to the router which now had no internet access, and.  And.  And with juggling the phone and tapping the keyboard I inadvertently disconnected the phone line.  And no way to get back to that technician, who was probably one of many located in a distant country.  So stuck in the middle just before reaching the promised land.  I again did the hard reset and got the modem back to routing mode and internet access restored.  And took a deep breath and more research.

Having got so close with the one technician I tried the provider again and got another guy who offered to establish a home net work for a $7.99 monthly charge – NO THANKS, and then had no idea on how to set up bridging.  So I was back to my own resources.

I located on the internet the router settings for when the modem is in bridging mode.  But I also discovered the modem could be instructed to do port forwarding as I had done with the router.  I discovered this fortuitously.  I had kept notes of how I enabled remote access of the DVR at the farm and the notes stated that I had configured the Actiontec modem for port forwarding.  So instead of bridging I googled port forwarding for the Zyxel and got the instructions (could not have figured it myself) and configured the Zyxel modem to port forward to the router (needed the router address) and to open the same port (15961) which the router had opened.  You can tell when you are successful – you go to canyouseeme.org site which will tell you your external address and you enter the port # (15961), and this time I got green colors and “success”.  And the proof of the success was when I accessed the cameras remotely and they all came up.  So a long tale of tribulations which would be even longer if I included all the miss taken dead end alleys.  But I got there (a second time).


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