Nighthawk C7800 losing internet connection often

[aaronsnay]

Hello Everyone, 

Thank you to everyone in this community. I've search this community for my issue which I've found several threads but the more I read the more I realize I don't know much! I have a Nighthawk C7800 with hardware version V1.07 and running firmware V6.01.07 and COX communication is my ISP. This unit was purchased new last December 2020. It worked flawlessly till a couple months ago. It started dropping the internet connection intermittently maybe once or twice a night. However, as this problem persist it seems to drop much more often, almost to the point of being completely unusable. I tried contacting Netgear when I first had the issues and they helped me once until they realized I was out of the warranty period. The tech had me switch the channels to manual and make some other adjustments to the CTS/RTS Threshold (I believe not entirely sure this is the parameter I adjust but I believe it was, I also don't recall the setting he had me input). This worked for a couple of days and the problem returned. After trying different channels to know avail I reset the modem to factory settings. I had a COX technician come to my house 2 days ago. He said the cable running from the street to the house needed to be change. I had him check the connection after changing that cable and he said everything was fine. The internet worked great for 24 hours and the problem came back. I've tried to monitor the logs and I see where I am getting Dos attacks which I've read on one of the threads could cause this issue. I've brought this up to COX and asked for a new IP address with their response being they don't write new IP address the only way I could possible get one is to leave the equipment unplugged for 48 hours. I'm not sure this is sole problem but I know I have lost connectivity after I have see them in the logs. I have included pictures of my cable connection page and event logs, I took these after having to unplug the modem to regain connection. If I need to included the regular logs please let me know. I also have COX technician schedule to return tomorrow. Any help would be greatly appreciated! 

[plemans · Accepted solution]

According to your logs, you've still got line issues. 

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

[plemans · Accepted solution]

According to your logs, you've still got line issues. 

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

[aaronsnay]

Thank you @plemans! The second technician was an actual COX employee and not just a third party contractor. He did confirm that the wiring in the house was too old and help me change it out at no additional cost. Everything has been up and running great since then. Thank you again for taking the time to confirm this before they arrived. 

[plemans]

Sad to see it was the wiring in the home causing the issue but glad you got it fixed. You got lucky with the cox guy as they usually charge for fixing issues inside the home. 

Either way, glad its fixed!