IPv6 connectivity issues with Nest Wifi Pro and Verizon Fios

[epyon9283]

I recently switched from an Asus Zenwifi XD6 to the Nest Wifi Pro. I'm currently using Fios as my ISP. The main nest wifi point is connected via ethernet to my ONT. 

Ever since switching to the Nest I've been having IPv6 connectivity issues. IPv6 is enabled in the google home app and my end devices are receiving IPv6 addresses. However, every two hours my devices lose IPv6 connectivity. This condition lasts for a few minutes and then connectivity is restored. When this occurs I seem to frequently get a new prefix.

I contacted google support. They checked the router and it showed unknown for IPv6 status and that I wasn't getting IPv6 from my ISP. I showed them screen shots of my IPv6 addresses and they said:

"7:58:30 AM Davidson: All routers provide IPv4 and IPv6 IP addresses on each device like IPv4 in the front end and IPv6 in the back end. This will help the device to disconnect once IPv4 reaches its limit."

At that point I ended the conversation since they didn't appear to know how IPv4 or v6 works.

I then contacted Verizon who stated that the DHCP lease time for v6 addresses is two hours but that everything on my ONT looked normal. They we're unable to provide any other assistance since I'm not using their router.

In the google home app I never see an IPv6 address on the main router even though the hosts on the network have them. Is that normal? The app shows IPv6 addresses for the connected devices but they're all out of date because the prefix keeps changing so frequently. 

[PatrickP_Viking]

This is likely due to the ISP refreshing your WAN address. If Verizon will not give you a static IP on Fios (think they charge an extra cost) then there is nothing the Nest Wifi Pro can do. Whenever the WAN IP changes, so will the IPv6 addresses.

Unfortunately, this is an ISP issue and not a Nest Wifi Pro issue. Unless they will provided (or you pay in some instances) a static IP, there is nothing little you can do outside of disabling IPv6 in the settings.

[epyon9283]

This was not occuring with my old router. Just because the lease time is two hours doesn't mean you should lose connectivity every two hours. The router should be renewing midway though the lease. 

[PatrickP_Viking]

If the ISP changes the IP address, the Nest Wifi Pro will request an IPv6 prefix which it uses to assign them to networked devices. If the ISP is not providing a static IPv4 and subsequently a static IPv6 prefix, the IPv6 will change whenever the IPv4 address changes or at the interval they have set (in Verizon's case every two hours at least).

This article explains it in more detail:

https://support.google.com/googlenest/answer/6361450?hl=en 

[epyon9283]

The ISP isn't changing the IPv4 address every two hours. That address doesn't change unless I release it or reboot the router or ONT. 

The router is obtaining a IPv6 prefix via dhcpv6. It SHOULD be renewing the prefix so that the ISP doesn't change it. It appears to me that this renewal either isn't occuring or isn't working. 

If Verizon was purposely changing everyone's prefix every two hours it'd make IPv6 unusable.

 Short of getting a network tap or hub, putting it between the router and ONT, and capturing all the traffic, is there any way to troubleshoot this on the router itself? As I said before, Verizon won't help when using a third party router.

[PatrickP_Viking]

Hey @epyon9283 .

I did a search regarding Verizon Fios IPv6 and they do in fact refresh the IPv6 prefix which results in the subsequent refresh happening with the LAN. Because Verizon Fios only assigns static IPv4 and IPv6 addresses to businesses, you don't have a lot of options here outside of disabling IPv6 on the Nest Wifi Pro, unless they have a residential option for static IPs. 

When the router requests to keep the current WAN IP address from Verizon, Verizon will advise if that is possible. If they have refreshed the WAN IPs, then it will deny the request resulting in another negotiation for the new IPv4 and IPv6. This then trickles down through the LAN and the changes reflected.

This article will assist with narrowing down the issue but I am nearly 100% sure this is on Verizon Fios: 

Fix your Google Nest Wifi or Google Wifi network 

Here's just a minute snippet of the articles I found with others having the same issue as you are and on various routers:

Learn about IPv6 (from Verizon Fios Support) 

IPv6 Routing settings (from Verizon forum) 

Beware of Verizon FIOS IPv6

IPv6 Issues (Reddit) 

Adventures with Verizon FiOS IPv6 (Hacker News) 

[epyon9283]

I just dug out my old managed switch and configured a monitor session on it. I'm now capturing all the DHCPv6 traffic between the router and the ONT so I'll know for sure.

[epyon9283 · Accepted solution]

Ok so it does appear to be the ISP at fault here. The router attempts a renew and the reply from the ISP is "NoPrefixAvail." The router then makes another request and gets a new prefix. I'll try to get Verizon to take a look but I'm not too hopeful. 

[PatrickP_Viking]

Thanks for the update @epyon9283 . Unfortunately, we are at the mercy of ISPs and sometimes hard to understand logic. 

Let me know what they say and if you are able to get something sorted out with them.

[Jeff]

Hey epyon9283,

I wanted to check in and see if you were able to get anything worked out with your ISP on this. Were they able to provide a solution that has things working well for you? Are you still running into the same difficulty?

Thanks,
Jeff

[epyon9283]

Hi Jeff,

I haven't had a chance yet. For now I've just disabled IPv6. 

[Jeff]

Ok, no worries epyon9283.

We can keep watching things until you get a chance to find out more from Verizon. Just feel free to update if anything more changes.

Thanks,

Jeff

[Jeff]

Hi again, epyon9283. I just wanted to follow up and see if you had a chance to speak with Verizon and to see if you found anything else out from their end. If so, just let us know and we'll be happy to continue helping.

Thanks,

Jeff

[AbigailF]

Hey epyon9283,

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

Cheers, 
Abi