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ebs's profile

New Contributor


9 Messages

Sun, Jul 26, 2020 1:00 PM

IPv6 over IPv4 (6in4) seems to be blocked


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.


Official Employee


526 Messages

2 y ago

Thanks for taking the time to reach out to us regarding your IPV6 issues. I am so very sorry to hear that you are having this trouble.  I very much appreciate your patience and greatly apologize for the delay in our response. I know how important the services are to your business and we want to do all that we can to assist. I would love to look further into the issues that you are experiencing with your services and the blocked device. Can you please reach out through private message with your first and last name, full-service address and account number or phone number?