Router losing connection to Cable Modem

@kenne04

This is definitely an interesting bit of news, thanks for sharing.

I have experienced the same problem for about the same time-frame as this post has been running. Very frustrating and my wife can't understand why this hasn't been resolve. Whether it's Cox's fault or Apple's fault, I don't care. I just want my internet to work uninterrupted. I hope Cox and Apple can get this resolved soon as this post is over 6 months old. I also noticed that some folks have had problems with other routers other than Apple so it's obviously not just a Cox/Apple problem. I have tried the latest suggestion of going through Google. We'll see what happens!

kenne04

f the problem is with Cox's implementation of IPv6, switching servers could solve the issue.

How so? How does DNS play a role in IPv6? Performance maybe, but you don't even need DNS to get a IPv6 address. 

kenne04

The DNS settings in your router basically tell the router which servers to connect you to.

The DNS settings tell the router which DNS servers to connect to. It has nothing to do with DHCPv6 or getting a IP at all. Heck you can get online without DNS, if you know the IP of the website. DNS is like 411 for the internet, allowing your computer to look up the IP(phone number) of the website (address). 

I mean if this worked for you, great. Don't mean to dismiss your idea and help, just trying to make sense of it. Maybe its just Cox's DNS server is slow to respond to AAAA requests in the way the Airport router is passing them. Using 3rd party DNS is usually a good idea in general, being faster and more secure. If you want to check for yourself, check out Google Namebench. Also, I would suggest making your IPv4 stack DNS also be Googles, or you might get some conflict. 

@TonyT

Once you go into the Airport Internet connection settings and set IPv6 to link-local only your connection should be good.

Another one with the same problem... For the past month I've been struggling with the internet connection cutting out. Unfortunately, a Cox contracted company has spent a lot of time and money replacing coax lines, connectors and our modem. The supervisor kept saying, "I don't want to say it's your modem, but it's probably your modem". Finally, this forum has provided a potential solution. After installing a new Apple AirPort Extreme, because I thought the technician could be correct that it was my router, the problem was even more frequent. I just tried switching to the recommended settings from IPv6 to Link-Local Only. It seems to have fixed the problem. Our neighborhood has had Cox Gigablast wire installations tearing up the roads. At first I figured this was the problem. I'm hoping the Link-Local Only is really the fix. I would think that Cox and Apple would save time and money if the two of them sorted this out. But I have to thank the B.E.W. (Cox contractor) supervisor who has worked so hard to help resolve our problem. 

The issue is actually with the AirPort, but disabling IPv6 does help the issue.  When the internet is "not working", the actual problem is the AirPort isn't responding to DNS queries.  You can still ping, ssh, telnet, or otherwise access traffic through the AirPort without issue.  DNS queries (UDP) to external services also work without issue.

The AirPort DHCP server only hands out it's self-IP-address to clients for DNS queries, rather than passing the ISP DNS settings on through to the clients.  Because of this, the AirPort becomes a single point of failure if it's internal DNS resolver fails to respond to queries.  The internal DNS resolver seems to have an issue with DNS resolution on Cox's network.  If you disable IPv6 on the AirPort, it will work for a while, but that doesn't solve the issue of the DNS resolver failing to work.  Changing DNS settings on the client (override DNS in Network Preferences) will also get you back up and running, though it's a manual setting that shouldn't be needed.

I think Apple should update the AirPort firmware to allow the passthrough of the ISP DNS settings to DHCP clients.  There's no need for the AirPort to be in the middle of that conversation anyway, and the ISP can and does provide redundant DNS servers in the event one is down.

somethingmoreunique

AirPort becomes a single point of failure if it's internal DNS resolver fails to respond to queries

This is the best explanation of the Apple IPv6 issue I have ever heard. Props!  I also heard a work around of using the apple utility to find out Cox's IPv6 DNS servers then manually enter them as static DNS for the IPv6 settings like seen here. Others just use Google's IPv6 DNS server 2001:4860:4860:0:0:0:0:8888 and 8844 which gets rid of the redirect traffic and Cox's slow AAAA responses. 

somethingmoreunique

I think Apple should update the AirPort firmware

I agree. This isn't Apple doing something to protect the customer, this is sloppy design IMO. Automatic DNS relay should only apply to IPv4 traffic until Apple can make it user friendly.

Hard coding IPv4 DNS entries worked for me as well but all I did was hard code the Cox IPv4 DNS addresses instead of allowing the Airport DNS to auto set them.  My only remaining issue is an edge case I'm still working on where Cisco AnyConnect resets my connection every 20 min on the clock.  I have not hard coded the IPv6 DNS addresses so perhaps I'll try that as well.

Add me to the list of unhappy, frustrated SoCal internet Cox customers.

About a year ago, (mid 2015), I started having this problem:  Modem blinking all normal lights, Apple Time Capsule (current gen, current firmware) losing internet connection (amber light).  Modem was a few years old, never had issues with it before, worked in previous SoCal address with Cox service flawlessly.

After Cox sent two techs out (not Cox employees, but contractors working for a company named "Sunshine" who do NOT have the proper diagnostic tools, such as a laptop with an ethernet connection!), they advised me that my modem was rather old, and I should go purchase a DOCSYS 3.0 compatible modem.  Reluctantly I did so.  Got an Arris Surfboard SB6121, which is fully compatible with Cox as per Cox support site.  Same problems kept happening, going offline every few days, several times a month.

So I considered maybe this was an Apple issue, saw lots of people on the forums (apple and cox) with Time Capsule and Airport Extreme issues with Cox, so I tried the link-local mode on the Time Capsule, tried disabling IPV6, nothing worked.

So I bought ANOTHER new piece of equipment, a new Linksys WRT1900ACS router.  Was disappointed in the fact that I lost the ability to do wireless backups as the Linksys does not support Apple's Time Machine backup software, but was willing to try another router just to eliminate the idea that this is Apple's fault.  Set it up in about 20 minutes, was working quite well for about 5 hours, then bam, went offline JUST LIKE THE APPLE ROUTER.  I thought, well, maybe this is a fluke and unrelated to my main issue, so let's be patient.  That was last week.  It went offline again a couple days later.

I setup the Apple Time Capsule again (default settings), and called Cox to send a Supervisor this time.

Instead, they sent a guy from the same "Sunshine" company, who AGAIN did the same routine of checking connections.  And within an hour of the tech leaving, it went offline again.

Hooked up the Linksys router again, default settings, went offline again yesterday.  Cox said, we're so sorry, we will send a Supervisor to you house.  So today, they sent 2 techs from Sunshine again (NOT supervisors), but they brought a NetGear Modem/Router all in one unit.  It is currently setup, and now we are waiting to see how this device performs.  At this stage, I am leaning towards my Surfboard 6121 modem being the culprit, but who knows.

I will update when this is all sorted out, good luck to all who are in the same boat.

I'm just reposting this becuz of the long term success I've had since adjusting my Apple Time Capsule's settings to link local. It's pathetic Apple hasn't patched this yet. Hope this helps customers who are new to the tread: 

had an Apple Time Capsule(2013 tall version) w/ a Moto SB6121 w/ no problems for 2yrs. Bout 3mos ago, out of nowhere, I suddenly kept losing my connection twice a day. Soon as I rebooted the modem or the router everything was fine, but it would always return. Went to the Apple forums and learned that Apple and Moto Surfboards don't play nice w/ each other(there's an entire thread devoted to it). I'd had no problems w/them 2gether for 2yrs previously though soooo??? Problem persisted, switched to my old Cisco DPC3000(DOCSIS 3.0).  Problem still persisted, so it's not that Apple/Surfboards don't like each other, becuz it's doing it w/ the other modem too. This is the solution that has worked for me without a drop/issue for a month straight: ***I changed IPv6 settings(in the network settings and Airport utility) to link-local***. I tested it w/ my old Cisco DPC 3000, my Arris/Moto Surfboard 6121, and now my new Netgear CM-500(had to upgrade to it to reach the new Cox 300mbps speeds). NO DROPS W/ ANY OF THOSE MODEMS ANYMORE-haven't had an issue since. YOU MUST SWITCH TO LINK-LOCAL IN BOTH THE NETWORK ***AND*** THE AIRPORT UTILITY. Just changing one won't work.

1. System Preferences/network/advanced(lower right)/TCP-IP/configure IPv6:link-local only

2. Finder/applications/utilities/Airport Utility.app/click on the Airport icon/edit/internet/internet options(below)/configure IPv6: link-local only/save

Hi Kurt2112,

Thank you for your post! Please let us know if you experience disconnects with the new Netgear Gateway. My team can take a look at what's happening!

It's not just the Apple routers. My Linksys WRT1900ac started this a few weeks ago, and some at work using Netgear N600 and NightHawk models are all reporting the same issue. I've monitored my neighborhood and see everyone with squarewave signals when the downtime happens.......except me after changing one item. I have disabled IPv6, deciding not to address thru DNS changes until COX resolves the issue. Since the change, I've logged only 1 downtime this week, vs 3-4 times a day, and that's not counting 9 hours a day I have my system down to standby since I'm not home.. If it were the routers compatibility or settings in support of IPv6 and DNS config, then why so many "modern and updated with latest driver" routers seeing issues? I for one just don't want to waste time on it, and am NOT willing to beta-test a system upgrade in process. I can live with IPv4 until the issue is addressed. Cox, how about regular status updates on the issues with IPv6 and estimates on correction/completed implementations? This is wasting a lot of hours that thankfully are mostly not billable.

Apple just came out with a new 7.7.7 firmware this month. They apparently haven't updated from 7.7.3 since 2013.

Does the new TimeCapsule firmware fix the problem?  Anyone know if the update even addresses the issues?

ElDiablo

Anyone know if the update even addresses the issues?

Issue was addressed, but haven't heard any feed back yet if it fixes the issue. From DSLR Cox employee:

"none of those notes mention the specific fixes that went in related to IPv6 and DNS but they are in there. We've confirmed this with Apple."

@Tecknowhelp

Thanks for the link. If there were truly fixes for IPv6 and DNS in the firmware releases, they might be working for me (Chandler, AZ).

I posted in another post about the firmware releases and that it didn't seem to help. I went back to using IPv6 yesterday and have had a stable connection for 24 hours and counting. I'm not sure why the previous test didn't work, but it appears to be working now. Time will tell.