Router losing connection to Cable Modem

Less than 1 hour later. Went down again. This time I was in the room. Nothing changed on the lights to the modem. Nothing on the Router. I did a ping to the modem on the internal LAN address. It was reachable intermittently.  I waited a few minutes and the router indicated no internet. So I rebooted the modem. Internal LAN IP became unreachable even after reboot. Rebooted the router - still no connection. Changed the router from static back to Dynamic DNS and Internet IP. Still nothing. A few minutes later ping started responding again and everything cleared up without my further intervention.

I'm still unsure of what this is telling me.  I do have another brand new modem in the box (Netgear CM600) - have been holding off just in case the problem was not hardware related.

I feel like I am back to square one. I've replaced both routers and modems, I have watched the signal strength, and logs, and nothing explains why this happens.

I'll take any input I can get. Calls to Cox technical support haven't gone far - they have seen a few modem reboots, but nothing else on their end to indicate a problem. But honestly - what else is left accept the wiring into the house????

Very disruptive tonight - I have a work project due in the AM and my kids went nuts when netflix and internet died!!

I have tried direct connecting during the day when it's just me at home, but I cannot leave it setup that way for a week as I have multiple devices in the network that my family uses (PC's laptops, streaming devices).

What I can tell you is that I have tried 3 different modems in addition to the 3 different routers and all combinations with the same issue.

I can also tell you that most of the time I can resolve the issue by rebooting the router not the modem, which led me to replace the Apple devices in the first place thinking there was some kind of issue with Apple and cable modems. That did not solve the problem.

The issue is that the router loses the LAN connection to the modem. So I suspect if I left direct connection to the modem for a week then I would maybe see a short blip if I was using the computer when it happened, otherwise, when I boot the computer it would get it's IP info from the modem and I would never even know anything happened. Don't think that is going to help resolve anything.

Here is some signal info - been watching things closely today - all looks close to range to me... hasn't deviated much all day either... Just one T3 when I was sleeping! :-)

Thanks... It's been stable the past 2 days again. I'm still really trying to understand what triggers the issue.  Still watching closely. Only seen one T3 error in the logs since the last reboot too. Watching..... Let's see when this returns.

I did set all my devices to static IP and set their MAC address up in the router - so nothing new can get added, and nothing can change on the LAN side (wired and wireless). Not sure if that will do anything - but it helps me eliminate another variable.

The one thing that was notable was my modem started responding intermittently to ping command right before it dropped from router last time.   It's sitting at 192.168.100.1 (rest of my devices are 192.168.1.XX

Maritn B - FYI you are not the only one going through this.  I have this at home and at my clients office.  Both devices involved are Airport Extreme routers.  I have a hard time thinking that this is not a issue on Cox side, being that I have been using both these routers on their respective networks going on YEARS.  It can't be a coincidence that they all go down at the same time.  Something on their network had to change to cause this problem. 

It's not just Cox, it's most providers. See post here. My guess is it's a issue with how IPv6 is being handled in the area. What makes it so difficult with Apple routers is they don't come with logging anymore. No idea why, since the old ones did, but Apple specifically took it out of the new versions. Probably the thinking was if more people know less about what is going on, they won't call Apple to fix it as much.

Sounds like some kind of issue with DNS proxy? Basically, the router intercepts the DNS request and sends them to what the router is getting for DNS via DHCP. Depending on the router, there is some caching done too. 

Has anyone confirmed the problem still happens when using another DNS like GoogleDNS(8.8.8.8/8.8.4.4)? I don't think the DNS is failing, because it works when you go hard wired, but maybe the DNS is just going down for a short time. I know the DNS servers are being worked overtime to handle new IPv6 requests, so that may be part of it.

Also, have you tried disabling IPv6 on the router?

Yes,  I had extensive conversation with Apple and they couldn't resolve it because it's not an issue with their router - out of frustration I got rid of 2 different model Apple routers and replaced with a Netgear recently and still have the same issue, Same with modems - I tried 3 different modems. I tried several combinations thinking bad hardware or incompatibilities. I tried new power outlets, UPS's and new cables for ethernet and coax. Nothing has improved or changed.

The issues isn't with a specific piece of hardware. So let's eliminate that variable. Something else in the environment is causing this kind of issue.  

It's intermittent too. It's been 4 days and fine - but last weekend it happened 2x and the week before went 7 days.  I've been watching logs closely for power or signal issues. It really seems like that's the root cause - but unless I can catch it happening Cox hasn't been helpful because they only are looking at the moment. 

I doubt someone wants to camp at my house for 4-7 days and wait for it! :-) But that's the challenge. Been going on for 3-4 months now. Prior to that - not a single issue in 10 years.

Very close to pulling the trigger on Centurylink service. Been doing my research. Will cost me about the same for bundled phone, internet, and TV. Unfortunately it may be time to make the change. I can't keep spending unlimited time and money troubleshooting signals into my house or disconnecting my entire LAN on witch hunts.

@Technowhelp - Yep... I have had IPV6 disabled for a while - both on the Apple Routers and on the new Netgear... Doesn't make a difference. Also have tried static DNS and Static IP to all my devices just to rule out DHCP and related issues - that hasn't improved anything either.

Tecknowhelp said:

It's not just Cox, it's most providers. See post here. My guess is it's a issue with how IPv6 is being handled in the area. What makes it so difficult with Apple routers is they don't come with logging anymore. No idea why, since the old ones did, but Apple specifically took it out of the new versions. Probably the thinking was if more people know less about what is going on, they won't call Apple to fix it as much.