Comcast Modem’s & DDNS

Comcast Modem’s & DDNS


Okay so my Comcast modem gave me such trouble with DDNS that I figured I’d write a post about it.

What I was trying to do

I was trying to set up an IP camera with a hostname address from No-IP so I could view it from outside my network. The problem is my Comcast modem had no default DDNS support, and when I did visit my IP it would not open the appropriate ports even though they were forwarded. It took awhile but I did find a permanent and correct solution.

What I did to get DDNS working

You need your OWN router for this to work.

So what I ended up doing was putting my Comcast modem into bridge mode you can do this by logging into your Comcast modem by putting into your browser’s address bar.

Once you are logged in you should see something similar except the only difference is instead of Enabled your’s should be Disabled.

Note that you will need your own router because what bridge mode does is pretty much turn off the router part of your modem, and make it just a “modem” in the traditional sense which is what we want.

bridge-mode ddnsAfter you do this assuming everything went smooth you can now plug up, and turn on your router so that it can start routing your internet to the various devices you own.

Now go to Google, and type what is my IP. It should be different than the regular IP you are usually assigned with just your Comcast modem. If so everything is a success and you can now use your own router to perform all household networking functions, and your Comcast modem will be just that a modem. Not a “2-wire” or a modem-router or nothing like that just a modem.


If things are not going as expected here are some things you can try that I know will resolve your issues.

Turn OFF your:

  • Modem
  • Router
  • PC

Than turn on your Modem and wait 30 seconds.

Than turn on your Router and wait 30 seconds.

Than turn on your PC and you should have internet.

You will know your Comcast modem is in bridge mode because it will say it is so in the web interface. Also the lights on the modem box will be different. The top 3 will be solid, and the two telephone lights will be flashing. If all else fails just disable bridge mode, and try again. It can be wonky sometimes so have patience its not broke (trust me).

I hope this post helped some of you guys!


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