Devices can't get IP address on LAN ports

[Dracsos]

Hello there, 

I am helping a friend figure out some networking problems and run into the following issue. 

Some ethernet jacks throughout the house have the problem that devices connected to it don't get an IP adress from the router. It's defenitly a problem with the port, because the same device gets an IP on a different jack in the house and vice versa. 

I first suspected it to be the cable inside the wall but because this problem exists on multiple jacks with different cables running through the that all stopped working at the same time, it seams unlikly. 

The ports on the switch that connect the jacks to the router all work normaly. 

I tried giving a device a static IP and then connecting it to one of the problem jacks but I get the same result. 

One of the devices is an VoIP phone base station and it shows if it's connected over ethernet. When plugging it in it shows that it has an ethernet connection over the problem jacks but doesn't get an IP address.

This also isn't limited to one type of device, it happend with an AP, the phone base station and Windows devices. 

 

For the networking setup, the friend has a FritzBox as a router and from there he has ethernet connections to 2 different switches. All the jacks inside the house are connected through those switches. 

The problem jacks not only on one switch. 

 

Has someone an idea why this is happening and how it can be solved? 

[Falcon1986]

17 minutes ago, Dracsos said:

Has someone an idea why this is happening and how it can be solved? 

Have you rebooted the Fritzbox and switches?

 

What is the make/model of switches?

 

If you think it's a problem with the switch(es) connect the ethernet run directly into the Fritzbox and test the cable. Should it work fine, then your switch is in need of replacement.

 

Inspect the exposed ethernet runs for any signs of damage. Tight loops or sharp bends can cause significant wear of the cable.

[Dracsos]

I have rebooted both the switches and the FritzBox and the same problem persists. 

 

Connecting directly to the FritzBox and the switches works and I get an IP address. 

[Falcon1986]

3 hours ago, Dracsos said:

I have rebooted both the switches and the FritzBox and the same problem persists. 

 

Connecting directly to the FritzBox and the switches works and I get an IP address. 

So it sounds as though there is a problem with the in-wall ethernet runs or the terminations at either end.

 

My approach to this would be to closely inspect the terminations of the “problem” runs for exposed twisted pairs or incompletely punched-down pairs at the keystones. Replace as necessary and ensure that the termination is using the same configuration standard at both ends.

 

If some of the ethernet runs are not in-wall, inspect these segments for stripped insulation or damaged wiring. Make sure no part of the cable is snagging on a nail or other object, or is punched down too tightly by U-shaped fasteners. Cables that run on the exterior of a building or in a crawl space under the house can be nibbled on by animals, so check on those too if this applies to you.

[Jsos16]

When cables are devices are connected are there any activity LED's on the switch or other device that light up? Could be the cable was become physically compromised. Can you do a continuity test on your cable runs?