Connectivity
Connectivity and managing Your Comcast Business network
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Occasional Visitor

IPv6 over IPv4 (6in4) seems to be blocked

Hi!

I've been using IPv6-over-IPv4 tunnel with Comcast Bussiness for a while without any problems.

Starting this Firday (Jul 24th, around 5am) all tunnel traffic (proto 41) seems to be blocked somewhere at Comcast or Comcast provided modem (CGA4131). Modem is in pass-thriough mode (all firewalling should be disabled according to the modem web UI). I suspect modem fw was updated and something got broken.

 

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14 REPLIES 14
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Official Employee

Re: IPv6 over IPv4 (6in4) seems to be blocked

Hello, how are you? I hope overall your weekend is going well. I apologize you are having trouble with IPv4 over IPv6. I know this must be causing an inconvenience. Are you able to send a private message with your name, service address, and account number (or phone number) so I can assist? I need to make sure your modem is online, and all your Comcast Business services are working properly.

 

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

I see today things are working again.

Modem firmware seems to have been reverted to CGA4131COM_3.12p14s3_PROD_sey, non working fw was CGA4131COM_4.2p3s4_PROD_sey

 

I'd like Comcast Bussiness to comment on what is going on and what is being done to prevent this from happening in the future - my service was affected for more than a week.

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Official Employee

Re: IPv6 over IPv4 (6in4) seems to be blocked

I will be more than happy to take a closer look at your account and equipment to see what I can discover. I am glad to hear you are no longer experiencing trouble. Firmware is always going to be automatically assigned to your modem. Are you able to send a private message with your account information so I can do all I can to help? 

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

I alerady sent you my account info in PM when you asked for it a week ago.

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Official Employee

Re: IPv6 over IPv4 (6in4) seems to be blocked

I apologize, I don't see a private message. Did you send it from this same profile? If you can send over another one, I can take the next steps to help. 

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

Just sent another one

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

Now I'm getting "You have reached the limit for number of private messages that you can send for now. Please try again later." when trying to reply to youR PM.

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

This started happening again today, around 6am.

I see that modem has been again updated to CGA4131COM_4.2p7s2_PROD_sey and it again triggered this problem.

Comcast folks, I was assured last time that the problem was known, why is this happening again? The lack of basic quality control *again* is amazing.

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Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

My tunnel to he.net died 3 days ago the same exact time yours did.  I'm running the same firmware.  What did you do to get them to revert the firmware on your CGA4131COM?  Customer support first admitted the firmware was deployed and then has now denied updating the firmware. I fail to see how a configuration that has been in place since 2016 all of a sudden has failed after maintenance on Comcast's part.  I also took a Cisco 2851 that was running IOS 15.1, wiped the configuration, setup a tunnel to HE.NET, and I see traffic going out but no returned packets.

 

Extremely angry and will be calling the Comcast Office of the President on Monday.  Comcast: You can't do this to your business customers.  You can't just blindly deploy firmware updates without testing appropriately!

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

First time it happened couple of months ago fw was reverted - I guess they found some other problems.

Now, after they pushed new fw, it doesn't work and Comcast so far haven't done much, I was asked to provide basic account info and some other irrelevant stuff.

 

Yes, this is Comcast incompetence and lack of basic quality control even *after* they were notified about the problem. I wouldn't be surprised that this info never actually got to the people who are responsible for fw rollouts, etc. I wish I could use some other more competent provider 😞

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Official Employee

Re: IPv6 over IPv4 (6in4) seems to be blocked

Good morning, thank you so much for taking the time out to reach out to the Digital Care Team here through the forums and we are truly sorry for the delayed response. I know how frustrating this can be when you are having issues with the IPv4 being blocked. You have reached an amazing team to help make sure we get this taken care of. Can you please send us a private message with your name, the full address, and the phone or account number? 

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

Update on the problem - Comcast tech support claims everything is fine on their end and it must be something on my side. There is no technical way they can claim that if modem firmware is broken - nobody has come to my home and connected test equipment to their modem to verify that claim.

So they just basically ignore what I told them numerous times about modem firmware.

 

Yes, this kind of support you get for the business service tier - "Everything is fine and it's a customer incorrect setup and is 'beyond our demarcation'". Which is ridiculous as they force you to use their crappy modem, so apparently hardware they force you to use and charge you every month is not their problem.

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Official Employee

Re: IPv6 over IPv4 (6in4) seems to be blocked

Thanks for taking the time to reach back out and provide the update. We can certainly schedule someone to the location for you. I will reach out to you via our private message to get this scheduled for you if you would like to go this route. I look forward to speaking with you again shortly. 

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Occasional Visitor

Re: IPv6 over IPv4 (6in4) seems to be blocked

I already told numerous Comcast employees what the problem was (yes, I wasted a lot of time troubleshooting this):

   New modem firmware blocks IP proto-41 traffic. Everybody just ignores it and keep saying everything is fine and it's a problem on my end.

 

This firmware version was fine - CGA4131COM_3.12p14s3_PROD

These two versions are not - CGA4131COM_4.2p3s4_PROD_sey and CGA4131COM_4.2p7s2_PROD_sey

 

Unless Comcast gonna send a tech who can troubleshoot this kind of stuff (e.g. can connect packet sniffer to modem ethernet port and use it) I know what's gonna happen - tech will come and will say everything is fine.

 

I can tell how Comcast can fix this problem without wasting more of my and their employees time - revert my modem firmware to CGA4131COM_3.12p14s3_PROD.

Alternatively, Comcast can report this problem to modem manufacturer and have them fix it in new firmware version.

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