Guest User!

You are not Sophos Staff.

Thread Info
  • State Suggested Answer
  • Locked Locked
  • Replies 12 replies
  • Answers 1 answer
  • Subscribers 29 subscribers
  • Views 1465 views
  • Users 0 members are here
Options
Suggested
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Xfinity Bridge Mode - Gateway Goes Down after 2 Minutes Following "Upgrades" to our Service

Cole Wilson2

Hey guys,

Since Monday morning (7:26 AM), Xfinity was "doing some work to upgrade your services" in my apartment complex. I have two XG home editions, running on different hardware, that are able to initially connect once putting the Xfinity gateway into bridged mode as usual, but after about 2 minutes (give or take a few seconds), the gateway just turns red and inexplicably I am not able to do anything.

This issue has persisted with V18.5.XX and V19, on two different pieces of hardware. Additionally, I've tried a real Sophos XG hardware appliance, the same result... 

It seems like something has been changed to me, almost exactly 2 minutes following a working connection it just turns red, and nothing can get past the default gateway. Is anything seeing anything similar with Xfinity home Internet gateways in bridged mode? I even had the gateway (the modem) REPLACED by Xfinity. It makes absolutely zero sense. 

I've run Sophos XG at home in my network since 2019. This is the FIRST time I've had issues, and I've had Xfinity in the past for 2 years, and AT&T for 1. 



This thread was automatically locked due to age.
  • 0 in reply to Cole Wilson2

    Nothing static should work and no spoofing should work. Your firewall should be a DHCP client of the ISP to get all of its information.

    Just to review: You have Cox Cable Modem --> Cox Firewall/Router --> Sophos Firewall --> rest of your network. And if you set the Cox firewall to its default (no t bridge mode, doing NAT, etc) everything works, but if you set the Cox firewall to bridge mode, you get two minutes and you have no upstream. When it all goes away, can you get traffic to the Cox firewall or modem? (I.e. which piece of equipment is shutting the connection down?)

    I guess it also needs to be asked: how are you putting the Cox firewall into bridged mode? Could that have changed with their upgrades -- due to, say Cox firewall firmware updates?

  • 0 in reply to Wayne Folta

    It's an Xfinity Gateway, so it's an all-in-one modem/router/firewall/access point. I believe it is manufactured by Arris. I am just logging into the default web interface and clicking the "Enable bridge mode" toggle as I've done with every Xfinity gateway I've ever touched. 

    Once it all goes away, nothing seems to make it past the private IP gateway of the Sophos LAN port. Although, if I specify the public IP that is assigned by Xfinity to the Sophos, I do get a response, of course, because of NAT. 

    I cannot reach beyond the gateway, in this case, 10.10.11.1 to be clear unless I specifically ping the public IP assigned to the WAN interface from DHCP. 

    The log will initially have an entry stating that the gateway has come up, 2 minutes later, the gateway goes down. 

Share Feedback
×

Submitted a Tech Support Case lately from the Support Portal?