04-21-2017 02:51 PM
i have an ERX v1.9.1 hwnat enabled with comcast and haven't had a problem with ipv6. maybe those having an issue could post their location, cable modem and CMTS model to see if there is anything in common there?
04-22-2017 05:53 AM
I am in Johns Creek, GA (metro Atlanta), have an Arris SB6183 modem and residental Comcast
connection. The cable connection comes straight into my computer room from a splitter. Only other
connection on the splitter is an X1 box in the den.
I have been able to get ipv6 working intermittedly with hwnat enabled. I upgraded to 1.9.7 alpha
yesterday and tweaked my settings. I had originally configured the switch ports as a bridge however,
I removed the bridge for the switch setup.
It is working at the moment. I did cycle power on the modem with my most recent test. That could be a factor.
04-22-2017 09:41 AM
04-23-2017 01:44 PM - edited 04-23-2017 01:52 PM
Can you enter the cli mode and cat /proc/cpuinfo and let me know the results?
mainly the cpu NAME mine is
cpu model : MIPS 1004Kc V2.15
Also the results from
lsmod | grep hw_nat
Or esle with an er-x that has ipv6 working on Comcast with hwnat.
04-23-2017 07:25 PM
So i havent posted before either about this but everyone here that says they have a problem with comcast on ipv6 i have the same problem too. I have an Edge Router Pro 8 port. I am behind comcast using their modem i dont have any pcap's or logs llike most folks have done because i havent had time to really look at this but i will say this my internet becomes completely unuseable if i upgrade to version 1.9.1 because of the ipv6 nat issue but if i back down to version 1.9.0 i have no problems it works like a champ. So there is definately a problem with comcast ipv6 and the edge router pro 8 and version 1.9.1 and nat just wanted to throw it out there that it also effects the ERPRO-8 please make sure if your coding an update to include the ERPRO-8 on this, i have been baffled since ERPRO-8 version 1.9.1 came out why i couldn't upgrade and everything came to a halt on my network and now i know why this forum actually shed some light on what happened to my nat.
04-23-2017 07:51 PM
So one thing to add, i tried the 1.9.7 alpha 1 release to see if the issue was solved and it wasn't so the issues still carries over to 1.9.7 alpha 1. I updated and my web browsing went to a crawl because of nat issues so im back on 1.9.0. I dont want to clog up the forum with posts and stuff but if there is a way i can help let me know what commands to run or give me a procedure to follow i want to make sure i dont have to stop using my router or be stuck on an old version forever if the erpro-8 isn't included on the comcast ipv6 issues fix. I am looking to upgrade to the newest 10gb router at somepoint when docsis 3.1 comes out so i really want to use your product i am a home user but i work on juniper, vyatta, cisco etc for a living but i dont get down into the weeds of the programming like this much
04-24-2017 05:42 PM
Thanks..Just wondered if all the hardware was the same. I have done a ton of experimenting.
The er-x and Comcast just won't work with hwnat offload enabled. You can get ipv6 working without
offload enabled and then modproge hw_nat to enable (on a running system) however, the ipv6
will die in an hour or two.
I only have a 150 mb connection so it doesn't really matter now. If I do upgrade it will be after
either AT&T gets fiber in here or Comcast really gets competetive with 1000 mb service.
04-24-2017 06:40 PM
04-25-2017 04:32 AM
I have an Arris modem SB-6183 (my own, not Comcast). It is a DOSCIS 3.0. It works great
I have had it about a year or less. I will update it at some point to 3.1 however, my speed tier
is 150mb and even hw offload is not necessary at this speed. I was looking ahead to see
if the er-x would suffice if I move to a higher speed. I do like it's features and you cannot
beat the price.
05-12-2017 09:10 PM
I am on firmware 22.214.171.124 and enabled hwnat for the first time yesterday.
So far so good, I have 3 VLANs, all devices are getting IPv6 addresses and pass the Comcast's IPv6 test.
Just let me know if you need to additional information.
05-13-2017 05:31 AM - edited 05-13-2017 05:35 AM
I still doesn't work for me. I am running 126.96.36.199 with the a slightly modified config that Steve Jenkins posted on github and here. (https://github.com/stevejenkins/UBNT-EdgeRouter-Example-Configs).
Without hwnat ipv6 works perfectly. If I enable hwnat, ipv6 disappears.
05-15-2017 09:32 PM
For those who can't get IPv6 working with Comcast, what's your CPU usage look like? I had someone post a comment on my blog that their CPU usage was high due to multiple IPv6 DHCP requests being made. Trying to see if that's a symptom affecting others.
05-16-2017 05:59 AM
What I have found is something in HWNAT is causing the DHCPv6-PD advertisements (source port 547/dest port 546) to be discarded silently. BTW I have this specifically permitted in a firewall rule and it works fine without hwnat enabled.
If you have it working and enable hardware NAT it will seem to work for some time as it will keep the existing address for its lifetime but will not be able to renew. If you reboot after enabling hardware NAT it will always fail immediately. I have tried permitting everything in my ruleset but that doesn't even get the packets to stop being dropped silently.
Software forwarding is keeping up for now.
05-16-2017 11:13 AM
I agree. I tried using different ports other than 546 and 547, tried tcp instead of udp but none worked
with hwnat offload.
There must be a way around it but I haven't discovered it yet.