My Orbi RBR752 drops IPv6 every hour or so.

Did Comcast/Xfinity tech support indicate how they provision IPv6?

I tried accessing their "IPv6 Test Site", but got no response (probably because I am not on their system).

https://www.xfinity.com/support/articles/about-ipv6 

I have been watching how Spectrum provides DHCP.

• IPv4 works exactly as one would expect.
  • Lease is for one day (86,400 seconds)
  • Orbi asks to renew at 12 hours
  • Spectrum issues new lease for one day within 0.2 seconds
• IPv6 is quite a bit different
  • Lease is for one week (604,800 seconds)
  • Orbi asks to renew in about 3.5 days
  • Orbi also does "Information Requests" much more often

It is not trivial to collect the interaction between customer router and ISP.  The Debug page option to "Capture LAN/WAN traffic fills up memory in a few hours and 'rolls over', so it is not a good method for capturing events that take place hours (or days) apart. What I did was

• Purchase a Netgear SG-108Ev3 (an 8 port switch cost less on Amazon than a 5 port switch)
• Insert the switch between router and ISP modem
• Connect one of the other ports to my PC (already using motherboard Ethernet port, so purchased a USB-Ethernet adapter, also from Amazon.  Got one that was mentioned on the Wireshark site as working in promiscuous mode.)
• Set the switch to mirror one of the router-modem ports to this new connection
• Set Wireshark to capture the traffic coming from the mirror port
• Use a Capture Filter (port 67 or port 68 or port 546 or port547).  This reduces the flood of traffic to only the DHCP packets. (IPv4 uses ports 67 and 68. IPv6 uses ports 546 and 547)
• In almost 3 days, Wireshark collected 90 packets and a bunch of them were not concerning my DHCP lease. (For some reason, Spectrum broadcasts DHCP ACKs and NACKs so they appear on my modem and get captured.)

This is obviously a form of obsession and not something most customers would attempt.

It occurs to me that the Debug capture option would be useful to capture when you discover that IPv6 is missing and attempt to get itback.  i.e.

• Start the debug capture
• Go through the IPv6 process until Orbi reports having an IPv6 address
• Stop the capture
• Save the debug zip file to computer
• Open the zip file and use a pcap program (I use Wireshark) to look at the file wan.pcap
• Use a display filter to show only dhcp packets
•  

cdysthe,

I also have Comcast IPv6 enabled, stateless (Auto-Config) instead of stateful (DHCP Server).  I'm using xFi Gateway as the main router to take advantage of Unlimited Data Plan and to avoid compatibility issues between Comcast/Netgear firmware.  My Orbi is running in AP mode and has no issue dealing with IPv6.  If you must have IPv6 enabled, an alternative option is available or continue to wait for a fix.  Good luck!

Do you remember any v4.x version of FW that has worked for you with IPv6 or has all been broke? 

If you don't, as recommended by SW, You should configure AP mode on the Orbi system and use your ISP modems router for IPv6 services until NG get this fixed. We don't know when that will be either so your best off using the ISP modem for now. 

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cdysthe wrote:
This is still an ongoing issue. I've seen on Reddit that many Netgear/Comcast users are struggling with this. My current procedure when it happens is to set IPv6 to Auto Detect. Takes around 30 second to be set to 6-4tunnel. Then set it back to DHCP. Wait another 30 seconds and I mostly have a new IPv6 address for a few days until it drops again. This has to be fixed soon!

---

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CrimpOn wrote:

Did Comcast/Xfinity tech support indicate how they provision IPv6?

I tried accessing their "IPv6 Test Site", but got no response (probably because I am not on their system).

https://www.xfinity.com/support/articles/about-ipv6 

 

I have been watching how Spectrum provides DHCP.

• IPv4 works exactly as one would expect.
  • Lease is for one day (86,400 seconds)
  • Orbi asks to renew at 12 hours
  • Spectrum issues new lease for one day within 0.2 seconds
• IPv6 is quite a bit different
  • Lease is for one week (604,800 seconds)
  • Orbi asks to renew in about 3.5 days
  • Orbi also does "Information Requests" much more often

It is not trivial to collect the interaction between customer router and ISP.  The Debug page option to "Capture LAN/WAN traffic fills up memory in a few hours and 'rolls over', so it is not a good method for capturing events that take place hours (or days) apart. What I did was

• Purchase a Netgear SG-108Ev3 (an 8 port switch cost less on Amazon than a 5 port switch)
• Insert the switch between router and ISP modem
• Connect one of the other ports to my PC (already using motherboard Ethernet port, so purchased a USB-Ethernet adapter, also from Amazon.  Got one that was mentioned on the Wireshark site as working in promiscuous mode.)
• Set the switch to mirror one of the router-modem ports to this new connection
• Set Wireshark to capture the traffic coming from the mirror port
• Use a Capture Filter (port 67 or port 68 or port 546 or port547).  This reduces the flood of traffic to only the DHCP packets. (IPv4 uses ports 67 and 68. IPv6 uses ports 546 and 547)
• In almost 3 days, Wireshark collected 90 packets and a bunch of them were not concerning my DHCP lease. (For some reason, Spectrum broadcasts DHCP ACKs and NACKs so they appear on my modem and get captured.)

This is obviously a form of obsession and not something most customers would attempt.

 

It occurs to me that the Debug capture option would be useful to capture when you discover that IPv6 is missing and attempt to get itback.  i.e.

• Start the debug capture
• Go through the IPv6 process until Orbi reports having an IPv6 address
• Stop the capture
• Save the debug zip file to computer
• Open the zip file and use a pcap program (I use Wireshark) to look at the file wan.pcap
• Use a display filter to show only dhcp packets
•  

---

Thank you for all that. Lots for me to look into. I asked Comcast a couple of months back when this started happening. They said they have made minor changes to DHCPv6 but not something I needed to worry about and that 'everything works as it did before". When I told them I use a Netgear modem and router they said "I think you have your problem right there". I didn't get any further. I have said earlier in this thread I have a feeling this has to do with Comcast's DHCPv6 implementation and Netgear firmware. But I am not expert in these matters.

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FURRYe38 wrote:

Do you remember any v4.x version of FW that has worked for you with IPv6 or has all been broke? 

If you don't, as recommended by SW, You should configure AP mode on the Orbi system and use your ISP modems router for IPv6 services until NG get this fixed. We don't know when that will be either so your best off using the ISP modem for now. 

---

cdysthe wrote:
This is still an ongoing issue. I've seen on Reddit that many Netgear/Comcast users are struggling with this. My current procedure when it happens is to set IPv6 to Auto Detect. Takes around 30 second to be set to 6-4tunnel. Then set it back to DHCP. Wait another 30 seconds and I mostly have a new IPv6 address for a few days until it drops again. This has to be fixed soon!

---

 

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FURRYe38 It worked up to February when this started to happen out of the blue. Whatever Comcast did to IPv6 at that time didn't sit well with Netgear firmware. I updated firmware back then when this started happening being told that it might help. It did help a little. Instead of having the IP drop every few hours I had the drops every few days and that is where it's at now.