Thoughts on this networking issue at work?

[ColdAsIce]

Bit of a strange one. We moved over to IPT for the phones. The port on the switch is configured correctly. Confirmed 3 times from our network team. However, the phone will not correctly pick up an IP through DHCP.

I thought either the network port on the wall was dodgy or the cabling back to the cabinet could be at fault. Tested this myself and it reported back with no faults. Ended up calling in our contractors with much better equipment to check the network port and cabling again. Everything is coming back as green. The port on the switch is also getting a signal as it's lit up without any error LEDs.

I've switched cables twice at both the network cabinet and the network point in the room to rule out a dodgy cable. I don't know where to go from here.

Has anyone seen this before when all test equipment is showing no fault on the lines but clearly there is an issue on route? Oh and it's CAT6 from run directly from the cabinet to the network port in the room.

 

[Armageus]

Sounds more like a switch/DHCP server issue than a cabling issue. I would start by looking at auto voice vlans and any settings on the DHCP server (assuming it's something like a Windows DHCP server rather than just a basic router DHCP server)

 

[ColdAsIce]

Sounds more like a switch/DHCP server issue than a cabling issue. I would start by looking at auto voice vlans and any settings on the DHCP server (assuming it's something like a Windows DHCP server rather than just a basic router DHCP server)

I've got 75 phones installed across the site without issue. Just this one line that is proving to be a nightmare. I've had the network team try 3 different ports as well as double/treble check the port configuration on the switch.

 

[VaderDSL]

Has the phone been tested? Does a known good phone work on the port in question and does the phone work on a known good port?

 

[ColdAsIce]

Plugging the phone directly into the switch port now and it’s working/downloading the settings and config. So it has to be a fault either with the cable run from the comms cabinet or the network port within the room. It’s just bizarre that zero faults have been found through the testing equipment.

 

[K.C. Leblanc]

Has anyone removed the faceplate and confirmed that it's wired correctly. If it's miswired the same way at both ends you can end up with something that tests fine with a basic tester but doesn't work.

Is it possible someone added another port by either daisy chaining or hiding an small switch somewhere.

 

[nox_uk]

Also check the faceplate for cake/other debris. It’s possible the higher quality pro gear has better/stronger connectors. My desk pre-covid needed a coffee stick wedged in to make it reliable