Odd ipV6 issue with Netgear CG3000CDR

I was delighted to see ipV6 turn up on my network a few weeks ago. But I'm encountering some issues. When i restart the modem everything works great, but within 8 hours (usually) ipV6 transit to the web stops working. I can ping the cable modem and my local clients all have what looks like valid ipV6 addresses but nothing can get out to the web (for instance, pinging Comcast DNS servers stops working) until I restart the cable modem.

No unusual settings on my network, this happens when I connect directly to the cable modem too.

Feels like either something is blocking me (is ipV6 in test maybe?) or something to do with ipV6 DHCP (which I don't understand as well as ipv4 DHCP)

Any advice would be appreciated as I'd love to keep using ipV6.

Sidenote: I noticed the ipV6 support is *not* checked on http://mydeviceinfo.comcast.net for the CG3000CDR but I'm seeing a lot of folks talk about using ipv6 with it, so maybe it is supported?

Hardware version 1.04, Firmware 3.01.04.

PS: This issue here sounds very similar http://community.ubnt.com/t5/EdgeMAX/DHCPv6-PD-Comcast-Business-Netgear-CG3000DCR-temporary-working/td-p/1111217

Responses

Accepted Solution

NetDog_Tuska

Problem solver

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90 Messages

10 years ago

I have my house behind the NetGear CCR and a Cisco 3845.. I did find some things odd like the lease time.. Take a second and look at this:

http://forums.businesshelp.comcast.com/t5/IPV6/Cisco-Routers-and-CCR-IPv6-sub-delegation/m-p/20948#U20948

Folks, I am seeing some strange behavior that appears to be related to DAD on popular Cisco routers and sub-delegated IPv6 prefixes. When the issue appears I see intermittent IPv6 connectivity from behind my internal router. This is what I had done to stable the router:

I found that if I enabled v6 DHCP on the NetGear Cable modem via the LAN IPv6 Setup Page and change the "Valid Lifetime" to 3600 all was good..

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Accepted Solution

NetDog_Tuska

Problem solver

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90 Messages

10 years ago

I am working with netgear on this issue..

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train_wreck

Gold Problem solver

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610 Messages

10 years ago

SO i haven't got any solution for you, but here is a post over at dslreports.com with someone who reports the same sort of issue with the Netgear:

https://secure.dslreports.com/forum/r29684257-

I will say, that there have been MANY reports of MANY problems with various consumer-level Netgear routers handling IPv6, in particular when it comes to prefix delegation/lease renewals. So it does not surprise me that there are issues with their cable gateways as well. (If you can't tell, I'm not exactly a Netgear fan 😉

IPv6 is still new to the BCI gateways, so I imagine it will take time to work out the kinks.

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NetDog_Tuska

Problem solver

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90 Messages

10 years ago

I am looking into this.. Oh and we dont "check the box" for about two week after we enable v6.. Just in case we have to disable it..

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cloudy

Visitor

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5 Messages

10 years ago

Thanks. Let me know if I can provide any data to help. I've run several tests and I can never seem to get past 15,000 pings, i.e. about 4 hours before external routing dies.

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cloudy

Visitor

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5 Messages

10 years ago

Thanks for the tip. I'll try that and should know by the morning if it helps.

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cloudy

Visitor

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5 Messages

10 years ago

That nailed it. Amazing, must have been literally the only setting I didn't try futzing with.

Setting the Valid Lifetime to 3600 (default is 60) sorted the problem.

Thank you!

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NetDog_Tuska

Problem solver

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90 Messages

10 years ago

sweet glad to hear it.. I have not had any problems as well..

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cloudy

Visitor

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5 Messages

10 years ago

Is there any value in letting somebody (who?) at Comcast and/or Netgear know? It seems like anyone with this router will start to experience weird networking issues as soon as they get ipV6. I have an Apple Time Capsule stuck on the back and it just starting sprouting ipV6 addresses which then caused connectivity issues.

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schuerger

New Member

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2 Messages

10 years ago

Please take a look at the "default" settings for IPv6. I see that I have the "valid lifetime" suggested by Comcast_Tuska, What about the "enable" check-boxes?

I have a very "vanilla" setup in my home office. I am not a network engineer--I provide remote BI, DW, DBA support. I have a university provided Aruba RAP plugged into the Netgear. The RAP supports an IP phone and university wireless in the residence. I have a Netgear WAP also connected for wireless users in the residence. My laptop is also directly connected.

My Comcast Business service is supposed to be 150/20 without any static IPs.

I note consistent difference between IPv4 & IPv6

I started this morning (onrebooted laptop plugged into port 3 of the Netgear)

0815am IPv4 @ 25/21 & IPv6 @ 168/22

1300pm IPv4 @ 11/19 & IPv6 @ 136/23 -- On the phone with Comcast - they are sending a tech out tomorrow.

1715pm IPv4 @ 11/18 & IPv6 @ 111/23

1755pm IPv4 @ 12/19 & IPv6 @ 94/23

Tracerout to the university VPN seems to be over IPv4.

When connected to the VPN terminal services connections are dropping..

The IP phone is now unable to acquire service.

Once it degrades this far, a full system reset seems to be my only option.

This is VERY bad when on conference calls or in the middle of server support.

Any advise/assistance will be appreciated.

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