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Rj45 ports lights on, service drops, wifi works

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Rj45 ports lights on, service drops, wifi works

I just upgraded after Comcast said my modem was too old, so now I have the technicolor xb3 dpc3941t. Randomly throughout the day, anything hardwired directly to the gateway disconnects but the wifi stays active. The device, upon ipconfig /renew just gives a 169.x.x.x ip address. If I swap the cables in the ports of two of my PCs, it works immediately. Anyone run into this before? I have three monoprice switches (no ui, no dhcp). I have PCs, echo dots, a macbook, apple tvs, smartthings hub, but nothing that should impact the DHCP, etc. Thanks in advance. Family beyond burned out about this.

UPDATE: I assigned static IP addresses outside the DHCP range, same issue. I get about 5 minutes into a show on the apple TV and it freezes. Some devices continue to function - I assume from not trying to reassign IPs, but guessing.
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Expert

Re: Rj45 ports lights on, service drops, wifi works

Try having it swapped it out to a different make and model number of the XB3 or an XB6 gateway device. Good luck !



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Re: Rj45 ports lights on, service drops, wifi works

This is the replacement 😞 thanks for responding though.
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Re: Rj45 ports lights on, service drops, wifi works

Second device, same exact problem, last one was an AARIS.
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Re: Rj45 ports lights on, service drops, wifi works

well, if you have the same problem with 2 different devices from 2 different vendors, wouldn't it be more likely that it has something to do with the rest of the setup?
The 3 switches are forming a tree (or star) topology with the modem/router as the root? There are no loops in the topology?
Also Ethernet has become more complex than it used to be. I had once an issue with the link to the AP, it would flap and the AP would not recover. Turning off the "green Ethernet" energy saving fixed it. Not saying this is exactly your problem but you may have a closer look at your switches.

Good luck 😉

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Re: Rj45 ports lights on, service drops, wifi works

First. I really appreciate any thoughts or feedback. Here's my layout for my rj45 ports. All four cables from my gateway connect to a different switch, so no loop back. I've removed my unifi APs, Ooma, and other devices to limit how many are on the network to see what device or switch may be causing it, but it keeps changing. I'll try to find the green savings right now.

I thought one of the switches was bad, but my apple tv kept freezing and having to reboot to keep watching a show last night, while my macbook (wifi off), connected to the same switch, continued to work. It's boggling. All four switches have no ui which I think is called unmanaged?

If I unplug and reply in the cable from my gateway to the device / switch, anything connected immediately works.
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Re: Rj45 ports lights on, service drops, wifi works

@CCKenF I've seen your name in a lot of the posts and hoping you can help.  The wifi from the gateway is always online and my internet is consistent, but when I swapped by old modem and router for a new gateway, it has been nothing but trouble for my hardwired connections.  My Mac hasn't had any problems (hard-wired through CalDigit), but SmartThings, Ooma, appleTVs, and LG tvs all drop regularly.  I took my unifi APs out, then Ooma, I just can't find out what's wrong.  The. apple tv will freeze for about 15-30 seconds, then resume, or sometimes will drop it's IP and only get a 169 regardless of how many times I reboot it.  However, if I ping it's IP from my mac, it comes back within seconds.  When the apple tv freezes, the ping times out for six attempts (seems to be consistent six timeouts) pings once, says "Ping: sendto: no route to host", then it's good again.  Thoughts?

 

UPDATE: The switches I use (and swapped around to test) are Monoprice  15762 and Monoprice 10927.  I thought about an issue with jumbo frames but don't know how to change the MTU on my dpc3941t router.  I tried putting my old medialink router in-between, both in bridge mode and without, same scenario.

 
 
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Gold Problem Solver

Re: Rj45 ports lights on, service drops, wifi works

Hey there. 

 

Just want to confirm a few things, you've disabled DHCP in the gateway and have the switches handing IPs like a passthrough?

 

Ken


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Re: Rj45 ports lights on, service drops, wifi works

Currently I'm trying to remove as many variables as possible, so from the gateway i took out the router in between as forcing the MTU lower didn't help.  It's now just four switches from each of the ports connecting to different devices.  I just don't how devices on the same switch have completely different experiences.  I've swapped their cables, tried static IPs, I'm just at a loss.  I can't see a way to PM you @CCKenF , but if you could call the # on my account or text, I can explain more of the scenarios I've tried over the phone or try things in realtime.  Thanks again for your help.

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Re: Rj45 ports lights on, service drops, wifi works

If I moved the DHCP to my other router and disabled it on the gateway, it's ok not to use bridge mode so I can use the wifi from the gateway?  I'm trying another configuration with the DHCP doing the wifi and all hard-wired devices through the router to see if the DHCP issues are specific to the gateway.

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Re: Rj45 ports lights on, service drops, wifi works

Sounds like a complex setup ... you can have 2 routers in-line, e.g.

gateway-router --- your-router --- switches --...
with both bein routers and DHCP enabled. In fact "your-router" still needs to know how to default-route, so unless you configure that statically it needs a DHCP information from the gateway.
And if you want to use the WiFi from the gateway then - unless your gateway allows some fancy segmentation of the 4 Ethernet ports (?) - you need DHCP on the gateway to provide IP addresses to the WiFi clients. You will also need the NAT functionality to map everything to the public outside IP, so bridging for the gateway is likely not possible ...
(take all with a grain of salt, I may not fully understand your setup)

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Re: Rj45 ports lights on, service drops, wifi works

Agreed. I'm just at wits end trying to identify the problem. I have a cable tester coming in the next day for my house hardwiring, but there's no way all these cables just died the day I got a new router. Most devices plugged straight into the router have no issues, but my tv and the apple tv both are dropping their IP and then cant get a new one. The LG TV works for about a minute and a half, freezes, and stops until I restart when hard wired. Wifi works all day.
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Re: Rj45 ports lights on, service drops, wifi works

I noticed the firmware is super old on my dpc3941t. I have DPC3941_3.14p4s1_PROD_sey. Can I manually update the firmware to the latest comcast supports? @CCKenF
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Expert

Re: Rj45 ports lights on, service drops, wifi works


@Jotamo wrote:
Can I manually update the firmware to the latest comcast supports?

No. Their system automatically pushes out the firmware loads.



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