Dns Settings Keep Changing To A Default 128.7.7.3

Yesterday I had to change out our old modem for a new one from Cox Communications. The new one is stronger and can handle all of the Wi-Fi we have going on in the house. My husband is hooked up to wi-fi for his laptop. I'm hooked up to ethernet to my desktop and we have a TiVo DVR Recorder hooked up to Wi-Fi.

I get the Modem home and hook it up, and I start to have issues about 2 hours after installing it. Yet, it's actually not the modem itself. I am having issues with the DNS settings changing from 8.8.8.8 on the preferred DNS setting and the alternate DNS setting is 8.8.4.4, The DNS settings consistently revert back to 127.7.7.3, I did a scan with Bitdefender total security for malware, and nothing came back. I then started to have issues with Bitdefender to the point I had to uninstall it as it wouldn't let me reinstall the premium version back to the desktop. I then purchased Norton Security and got that installed with no issue. I'm still having the same issue with the DNS and I just did a scan with Malwarebytes and so far nothing is coming up. Can anyone shed some light on this? I'm not sure what is going on.

 

Where do you set the DNS, separately on each device or directly on the modem/router via its interface? If the former then try setting the DNS you want directly on the router. As it's new you will probably need the manual for that.

 

I changed the DNS setting on the router, but the modem is new. How would I change the DNS setting on the modem.

 

I don't know anyone here (UK) who uses separate modems and routers as AFAIK all the mass market and ISP supplied routers here include a modem. So you have already done what I was advising. The router firmware must be hard coded to use 127.7.7.3. Personally I'd rather choose, buy and configure my own router.

 

Might be worth configuring one of the devices to use 8.8.8.8 to see if it can hold it.

 

I did a clean install of Windows 10, and set the computer back up, but the DNS setting keep reverting back to the 127.7.7.5. I have set the preferred DNS setting to 8.8.8.8, and the alternative to 8.8.4.4. but I keep getting the DNS settings reverted back to 8.8.8.8 and nothing in the alternative. Could this be a default DNS setting of the internet service provider of the 127.7.7.5?

 

I found the issue and it's not malware. I use a software for internet scanning to avoid malware called, "Heimdal Security Assistant" the DNS setting 127.7.75 is used for the software to monitor the incoming and outgoing internet to avoid malware. So all is ok and I know it's safe. Thank you for trying to help me.