Skip to main content

    Support

    Offers

ES2042's profile
ES2042
Discussion Driver
Rousing Reactor
Expressive Exchange

Contributor

 • 

102 Messages

Tuesday, May 17th, 2022 1:26 AM

Closed

XB7 - LAN Connection through Ethernet Ports on XB7 Dropping

have a XB7 since the release and it worked fine. Since a couple of days, XB7 is dropping connections randomly. Devices that directly connected via Ethernet are getting disconnected and dropping. Done everything (cable, reboot etc) and also exchanged the XB7 at Xfinity store. Still dropping connection. WiFi is still flawless

Question

 • 

Updated 

3 years ago

 • Edited

1.6K

3

flatlander3

Problem Solver

 • 

1.5K Messages

3 years ago

Yep weird.  That's two of you in two days.  Usually, Ethernet is pretty rock solid on everything.   I have seen a switch flake out and start spewing enough garbage (frags and runts) to take down a network if you use one of those.  Bad cable usually just a single port issue.  

Is your gateway getting hot?  Fan dragging/making noise? The thought is, there a bad fan might cause an Ethernet phy overheat -- they don't like that.  

In windows, from a CMD window try a netstat -s -t command and see if there's a bunch of errors.  Might show you which device is having issues.  Maybe they all will have errors but it's something to look at.  Other than that, plug one device at a time.  See if there's one that when plugged in flakes out everyone.

1

flatlander3

Problem Solver

 • 

1.5K Messages

3 years ago

Well DHCP RFC 2132 says the missing required option 2 is telling you that the dhcpv6 is missing a time offset from Coordinated Universal Time (UTC).  That's pretty weird and tells me a DHCP server is misconfigured.  If you aren't running one, that an Xfinity problem.

Option 82 has to do with relaying DHCP requests (forwards).  Also strange. 

On the Ethernet clients, if you temporarily disable ipv6 protocol, does it help?  https://adamtheautomator.com/disable-ipv6/

Might not be looking at an Ethernet issue at all.

1

ES2042

Contributor

 • 

102 Messages

@flatlander3​ thats a great finding! no, I dont run a DHCP server. I disabled ipv6 and zero impact :-( ok, back to Xfinity then and ask about DHCP issue. Here is another weird thing: I was not able to start the admin login now (10.0.0.1 page) and restart the gateway via app. After this I was able to login, but clients dropping every couple of minutes the connection. I did a restart of the XB7 via admin page... all messages gone in the log, no longer DHCP errors... Client connection stable for more than 1hr. And just got the next drop. And also a weird finding: not all devices that are connected are shown as connected devices at the XB7 tool. But I can reach them..

(edited)

3 years ago

0

flatlander3

Problem Solver

 • 

1.5K Messages

3 years ago

Wonder if you're getting flooded with a DoS attack, or suffering from traffic loads.  I don't know why you couldn't get to the internal 10.0.0.1 page unless the gateway is struggling with CPU usage.

As long as you're going to try to talk to Xfinity above tier 1 support, and if you can get to an actual Security CSA, have them unprovision, then reprovision your gateway.  See if they can get you a different ipv4 and ipv6 address, or cancel the lease and have you reboot it.  Doesn't stop a script kid from walking your subnet, but if a bot is fixated on your address, it might bump em for a while. 

In the mean time,  something else?  Disable Xfinity hotspot if you still can:  https://www.xfinity.com/support/articles/disable-xfinity-wifi-home-hotspot?linkId=165401606

Will it make a difference?  Meh, probably not.  Just another knob to turn to rule something out.

8

ES2042

Contributor

 • 

102 Messages

@flatlander3​ oh, the new XB7 had default setting for hotspot on.. lol, didn't check it. Thanks!

it looks like all 4 direct ethernet ports are the ones who drop most.

done again netstat -s -t but details shown are above my knowledge. Any advice? I think the only way is -as you mentioned- to get someone above Tier 1 support. It's truly a XB7 problem,  only effecting Ethernet ports. Again WiFi is flawless.

(edited)

3 years ago

0

flatlander3

Problem Solver

 • 

1.5K Messages

You're really just looking at the ipv4 and ipv6 error lines with netstat for this.  If they're way out of wack with high counts, it's telling you something odd is going on, but you already knew that.  You get to see which protocol is the problem though, so it might help Xfinity debug their end.  Just a data point.

Seems to be a lot of ipv6 issues if you scroll down the board.  Related?  Recent network change in your area too?  Dunno.

I'd be more than tempted too to not waste time on the phone, especially if I wasted my time and replaced it once.  Go to the wally world, buy a cheap approved gateway, Return the xb7 to Xfinity, and save $14/month rental fee.

I'm not seeing the point of xb7 devices.  Remote management isn't a feature, it's security exploit.  Other ways to do that if you really have to change a setting from somewhere else, but that need just doesn't arise.

Will it fix a network problem on their end?  Nope, but it may handle it better than their buggy firmware.  You can also set other DNS servers.  Theirs don't work very well.

3 years ago

ES2042

Contributor

 • 

102 Messages

ooh wow, checked the XB7 firewall log:

FW.IPv6 INPUT drop , 4721  Attempts, 2022/5/17 10:50:23 

FW.IPv6 FORWARD drop , 434  Attempts, 2022/5/17 10:50:23 

3 years ago

0

flatlander3

Problem Solver

 • 

1.5K Messages

My IP gets port scanned all the time.  Sometimes I'll leave a trap port or two open and see if I can stall the script kid with an adaptive firewall.  

If they have no debugging, it hangs their end.  If they do, at least I held them up/delayed them for a while before they moved on to the next IP.

The bot traffic on Xfinity isn't helpful regardless.

3 years ago

ES2042

Contributor

 • 

102 Messages

you know what... I switched off XFi Advanced Security... until then... all good. Cross my fingers, but it looks like that was it. I have a Synology NAS and also Plex running on it. Maybe XFi doesn't like it

3 years ago

0

forum icon

New to the Community?

Start Here