Airport Extreme and Cox Internet IPv6 Problem

Hi @gino_cerullo - Yes, I have tested using Google DNS.....still had issues.....changed Extreme to local link only.....no issues for over 90 days....

@hipsterpdx, well sure, by setting the AirPort router to Link-local you are effectively disabling Cox's IPv6. We are trying to find a solution that preserves the use of IPv6 and all the benefits in brings until Apple and/or Cox can work out a more permanent solution.

Thanks for your feedback. Sorry it did not work for you.

Thanks Gino_Cerullo.

This IMac with issues is connected via WiFi only and is pretty far away from the main router (Time Capsule), but there are three Airport Extremes set around the property including two chained as it were between this iMac and the Time Capsule.

Anyway - Firewall - none. Proxies - none.

For now, I have left the Google DNS settings in there - but I went into Time Capsule and under Network Options I clicked the box for "Block incoming iPv6 connections" and now the iMac is working on the internet. It seems contradictory to do the Google DNS thing and then click to block incoming IPv6 anyway, but that is the way I have it for now.

Oddly, when I go to http://test-ipv6.com/ on this WiFi connected iMac I get the same "Good news! Your current configuration will continue to work as web sites enable IPv6." and the same 10/10 green.

When I have more time later today I may just revert to the local link method until Apple or Cox figure something out. But for now this works.

Question - if I do revert to the local link do I need to as well click this "block incoming IPv6 connections" ?

Second question - is it normal to get download speeds of say, about 35 Mbps download via WiFi on a pretty new retina iMac (Late 2013) when the other iMac that is hardwired to the Time Capsule is getting 139 Mbps download? Speed goes down that much over WiFi? (Granted this iMac is maybe 300 feet away and several intervening walls away from the Time Capsule, but with two intervening Airport Extremes to carry along the signal.)

(And what is odd as well, is that the UPload speed between the hardwired IMac and this far away WiFi IMac isn't really that different, just a difference of a few Mbps.)

Oh and by the way - the level 2 Cox rep I spoke to said that the Google DNS method was a viable solution just like the local link method UNTIL she heard that I had entered Google DNS into the iPv6 two boxes - she was against that. Then again, what's the point of the Google DNS solution unless you provide the ipv6 DNS? Would it work to enter the two Google DNS servers at the top but leave the ipv6 DNS servers blank? Like I said, when I have more time later today I may fool around with settings more see what works and what doesn't.

You know, before I changed the DNS to those of Google, and I took a screen shot, the standard way my Internet was configured WAS with the two Cox DNS servers entered (they were actually gray but the numbers were there) and NOTHING (blank) in the iPv6 DNS servers - there just was nothing in those two boxes before I started altering things.

Hi CromeYellow, glad you got it working without disabling IPv6.

I posted something earlier about the "block incoming IPv6 connections" setting but I should probably explain all of the advanced IPv6 settings on that screen.

"Block incoming IPv6 connections" turns on the stateful IPv6 firewall.

The stateful IPv6 firewall blocks all incoming requests over IPv6 but it keeps track of all outgoing requests and allows answers to those request to be return to the computer or device that requested them. For example, when you're browsing the Internet your web browser is requesting web pages to be displayed. The stateful firewall keeps track of that request and allows it to return the computer or device that requested it while also blocking all other access to the computers on your LAN.

"Allow Teredo tunnels" allows the use of a specific IPv6 to IPv4 tunnelling protocol. Unless you are using Teredo tunnels you should leave this disabled.

"Allow incoming IPSec authentication" allows us to use one of the benefits of IPv6 and should be enabled.

One of the benefits of IPv6 is that IPSec is enabled for end-to-end IPv6 connections by default. IPSec is a security feature that scrambles the communication between two computers so that someone that may try to observe the traffic can't tell what is being transmitted. It adds a slight bit of overhead to IPv6 communications but the benefits outweigh the slight hit in speed. You should only disable this for troubleshooting purposes.

All of the above settings are the default settings when setting up a new AirPort router.

You also mentioned that you have other AirPort Extremes around your property. I presume they are configured in bridged mode to extend the reach of your Wi-Fi network. For IPv6 they should also be set to Automatically and Native. If they are configured to DHCP they will receive their DNS settings from the main router.

Now to the question at the bottom of your post. If you revert to Link-local your are effectively disabling Cox's IPv6 and you can disregard all of the advanced IPv6 settings discussed above and leave them at their default settings.

The other Airport Extremes are set under the Wireless tab to "Extend a Wireless network" and yes, then under the Network the Router Mode is grayed out to "Off (Bridge Mode)" ---

they are also set to Configure IPv6: Automatically

IPv6 Mode: Native

and then the "Enable IPv6 Connection Sharing" box is UNchecked.

However under the main Internet tab, these Airport Extremes are set to Connect Using: DHCP, is that not correct?

Thanks! again for your detailed help and effort.

CromeYellow wrote:

The other Airport Extremes are set under the Wireless tab to "Extend a Wireless network" and yes, then under the Network the Router Mode is grayed out to "Off (Bridge Mode)" ---

they are also set to Configure IPv6: Automatically

IPv6 Mode: Native

and then the "Enable IPv6 Connection Sharing" box is UNchecked.

However under the main Internet tab, these Airport Extremes are set to Connect Using: DHCP, is that not correct?

Thanks! again for your detailed help and effort.

That is all correct. You should be good to go.

CromeYellow wrote:

Oh and by the way - the level 2 Cox rep I spoke to said that the Google DNS method was a viable solution just like the local link method UNTIL she heard that I had entered Google DNS into the iPv6 two boxes - she was against that.

Wow, that is an interesting revelation and might explain why changing to Google DNS (or any other DNS but Cox) for IPv6 solves the problem.

I now suspect that COX has configured their IPv6 DNS servers out of spec and that is what is causing these headaches. They are probably gathering some kind of analytics which is why they don't want you to use any other DNS servers for IPv6.

I would disregard the COX representative and use any other DNS but theirs if it solves this problem. Using a third party DNS is not a violation of their terms of service, I checked. They do not mention anything about DNS in their Policy statement. https://www.cox.com/aboutus/policies.html

I have been having this issue for nearly a year. Multiple calls, three separate house visits by a cox technician, replaced my Motorola modem, Time Capsule, ethernet and coaxial cables, and no solution despite there being "no problems found."

I got fed up after dealing with resetting the Time Capsule every day for almost 3 months since the last visit and called again. They set up another appointment. I received a call from a high-level technician yesterday who nonchalantly told me the issue is related to this IPv6 setting and had me disable it.

I have not experienced any situations where I need to RESET my Time Capsule since changing the IPv6 setting - HOWEVER

CromeYellow wrote:

Second question - is it normal to get download speeds of say, about 35 Mbps download via WiFi on a pretty new retina iMac (Late 2013) when the other iMac that is hardwired to the Time Capsule is getting 139 Mbps download? Speed goes down that much over WiFi? (Granted this iMac is maybe 300 feet away and several intervening walls away from the Time Capsule, but with two intervening Airport Extremes to carry along the signal.)

(And what is odd as well, is that the UPload speed between the hardwired IMac and this far away WiFi IMac isn't really that different, just a difference of a few Mbps.)

THIS is now happening to me. My hard-wired iMac is getting the speeds that I expect of at least 150Mbps (though intermittently hangs when loading a webpage), but my iPhone will frequently dip to anything from 1Mbps - 60Mbps. When playing "Destiny" on my PS4 over wifi, it will have issues communicating with the destiny server - It will never completely disconnect from the game server, but it will lag and become unplayable until the network speeds back up.

I did not experience these speed and intermittent connectivity issues until after changing this IPv6 setting. It was definitely annoying to have to reset my Time Capsule every morning, but this current issue is far more impactful in an actual use scenario.

Edit: Added SpeedTest results from the same location (about 10 feet away from the Time Capsule).

I am just leaving it with the Google DNS settings for now, plus with the block incoming ipv6 settings and Allow incoming IPSec authentication boxes both CHECKed. Been all green all day on Time Capsule and the 3 Airport Extremes. Will report back in a few days, or if something bad comes up.

CaptainBlue how fast MY WiFi is depends on how far I am from the Time Capsule to the greatest extent, and to some extent how far from the relaying Airport Extremes. I emphasize the word MY because this applies just to me - if I am testing with an iPhone 6 plus right next to the Time Capsule, I get about the same speeds as the hardwired iMac, 130s Mbps download. But if I am at the far end of the property, 300 feet away from the TC and two Airport Extremes away, I can get as low as 20 Mbps download, or even 12 Mbps.

Those 20 - 40 Mbps speeds you describe ten feet away from your Time Capsule if your hardwired Mac is getting 150 Mbps at that exact moment are not normal. However, I think it can be normal to get half the hardwired speed on WiFi even from right next to the primary router.

The times I have seen the really slow downloads you describe - "1 Mbps" something has been wrong, specifically that one or even two Airport Extremes somewhere in the network have gone yellow and are not relaying.

Cox has never been too friendly towards any equipment you purchase - they are happiest when you are an indentured servant renting from them, and they seem particularly hostile towards routers in general (Tell them that you have a router and they will typically clam up and "blame the router" for whatever is ailing you at that moment), and are especially hostile towards Apple routers.

In fact, the level 2 Cox tech told me that they do not support or provide tech support for Apple routers except on this specific iPv6 issue.

I reverted this morning to the local-link setting. This morning although all lights were green on my Airport Utility, and even running Network Diagnostics returned the messages "Your internet connection appears to be working correctly" on both iMacs still for some reason on both the iMac that was connected via WiFi and the hardwired iMac I could not get any internet via browsers - nothing was coming up.

(Oddly at this same time via WiFi iPads and IPhone were working fine.)

With the local-link setting I get the same speeds - hardwired about 135 Mbps down, and about 14 up.

So for now I am just leaving it on the local-link setting. Cox is actually coming out to diagnose why I can't get more than about 135 Mbps on the hardwired iMac even though I am supposed to get 150 Mbps with their Premier Internet plan.

I am using a Zoom 5341 Docsis 3.0 modem rated to 172 Mbps. I offered to replace it with an unused Netgear CM400 I have that is rated to 340 Mbps but she didn't seem to think that would make any difference.

Thanks CromeYellow for posting back your results. Hopefully Apple and/or Cox find a more permanent solution to this problem.

Cox must be spending a bundle of money needlessly send techs out to homes to troubleshoot a problem they already know exists, but have yet to supply a proper fix for.

I ended up going with the local link only (hopefully temporary) fix until Cox figures out how to resolve the issue. I posted my up and down speeds earlier; however, I have no reference as I didn't check them before reconfiguring or before changing my modem or "upgrading" to the higher internet tier.

It may only be my imagination, but it seems like the iMacs are running slower while our iPads and iPhones are the same or better.

I wonder if Cox will notify us when and if they finally resolve the issue.

@CromeYellow - local link will give u stable connection.....(you don't need to be ipv6 at this time - I am pretty sure Cox / Apple will resolve by the time consumers need to be ipv6)...as I mentioned in previous posts, i have been configured to local link only for several months, Cox Premier, getting 300+ down and 30+ up with Airport Extreme and Arris SB6190 Cable Modem......

Also, in another location with Comcast, and EXACT same equipment I did not have to set to local link.....so issue appears to be with Cox....

As it relates to your download speed.....do you have the J or H model? See below:

"Download speed is up to 172 Mbps for Model 5341H (343 Mbps for Model 5341J)*. Upload speed is up to 143 Mbps. Actual speed also depends on your cable modem service."

Link: http://www.zoomtel.com/products/5341.html

If you want you can run a temporary test by connecting your computer directly to the Cox modem with the ethernet cable by-passing the AirPort router.