• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

169.254.x.x with a switch connected to a CGN3 modem gateway

S

Sincero

Junior Member
I have a CGN3 modem (Rogers) connected to a TP Link switch. This was working for many months but it has stopped working. Now, PCs get assigned 169.254.x.x when the switch is connected. Connecting directly to the modem is OK. Even those connected directly the modem-hybrid do not work any longer. The WiFi continues to work. Is this a DHCP issue?

  • I've tried factory resetting the modem -- no success
    Tried different Ethernet cable, nothing
    I've tried rebooting both devices with no success

When I had a previous modem/router hybrid things worked fine. However, lately things have been wonky. I managed to get it online once by letting it sit and plugging it back in but a couple days later it's back in this state.

I own this switch: http://www.tp-link.us/products/details/?model=TL-SG108

I own the rogers version of this modem/router: http://www.hitron-americas.com/products/cgn3/
 
Sincero said:
I have a CGN3 modem (Rogers) connected to a TP Link switch. This was working for many months but it has stopped working. Now, PCs get assigned 169.254.x.x when the switch is connected. Connecting directly to the modem is OK. Even those connected directly the modem-hybrid do not work any longer. The WiFi continues to work. Is this a DHCP issue?

I own this switch: http://www.tp-link.us/products/details/?model=TL-SG108

I own the rogers version of this modem/router: http://www.hitron-americas.com/products/cgn3/
Click to expand...

Bolded: are devices directly connected to teh CGN3 working or not?
 
Let me clarify.

If you connect directly to the modem with no switch attached, everything is okay.

If you connect directly to the switch or modem, where the switch is attached -- none of the ports work. That is, while the switch is attached none of the ports work.

Hope this helps.
 
Sounds like the switch is on the fritz....got a spare one to test with?

Are you always using the same port on the switch to connect to the Gateway? If so, try a different switch port to see if the problem going away. Switch ports themselves can go bad.
 
If you set up the switch, and give a workstation a static IP, does it work ok?

Have you tried plugging the devices into different power outlets?
 
I haven't tried a different outlet, and it'd take a bit of effort to do so, but I'll consider it. It's unmanaged -- and I've tried a static IP but no go. I just get told I have an incorrect configuration.
 
I think it's also worth noting that if I disconnect the switch, unplug everything but the ethernet between the router and the switch plus a ethernet cable to my my PC and plug it in, things are fine. If I slowly add wires to the switch, these devices come online slowly. However, after a short period of time everything crashes again. =/

Leaving the switch powered off for some time (2 hours+) and then reconnecting it also has a varying degree of success, but it disconnects eventually.
 
Last edited:
How many devices are there on the network? It's a long shot, but maybe you're using up your DHCP scope.

Have you double-checked your cabling to make sure you didn't accidentally create a switching loop?
 
I find it hard to believe I'd have a switching loop - there's only a single switch and the only cable running not from the switch to the PC is the router and switch tied together.

There's only about 12 devices total, I doubt this would use up the entire DHCP scope considering but is there a way to check? I know my rangs into the 100s

3GfJNO5.png


I remember setting the lease time lower in hopes it would help.
 
No, I don't. I'm using another gateway right now in the iterm (another router, Cisco DPC3825) and it seems to be working better... is it possible for a gateway to cause this kind of issue? I should have noted that a Netgear is also plugged directly into the modem -- which is for our "home alarm system". Presumably, this is in bridge mode? I'm not sure. The system will crashed without it, at any rate.
 
It's a good idea to let us know all the devices on the network. Odd issue like this can be caused by any device that's connected. If the network still crashes without the Netgear, then it's not a big deal.

My gut says your problem in the gateway. I would also check the power outlet with a multimeter, power issues can cause devices to act funky.
 
Hi,

I've swapped the gateway and am now using my Hitron as a modem only and my Asus RT-66U as a router -- it crashed today and this is the log contents:

http://pastebin.com/1MyykHQP

Any assistance is appreciated.

Here's my routing table, too:

Destination Gateway Genmask Flags Metric Ref Use Iface
173.32.86.1 * 255.255.255.255 UH 0 0 0 WAN
192.168.1.0 * 255.255.255.0 U 0 0 0 LAN
173.32.86.0 * 255.255.254.0 U 0 0 0 WAN
default 173.32.86.1 0.0.0.0 UG 0 0 0 WAN

(This is without my switch plugged in)


Here's a clean run:

I cleared the log. I unplugged the switch, connected, plugged the switch in. I verified I lost the ability to load webpages on my PC. Unplugged the switch, can load web pages now.

http://pastebin.com/CPqriwRW
 
Last edited:
You must log in or register to reply here.

TRENDING THREADS

Back
Top