Equipment isn't able to obtain an IP address on LAN ports
Equipment isn't able to obtain an IP address on LAN ports
Hello, I'm assisting a friend with some networking challenges. They noticed that various Ethernet ports aren't assigning IP addresses to connected devices. This clearly points to an issue with the port itself, as the same device receives different IPs depending on which jack is used. Initially, they thought it might be due to the cable inside the wall, but since the problem persists across multiple jacks with different cables, it seems unlikely. The switch ports linking the jacks to the router are functioning normally. They tried assigning a static IP and connecting a device to one of the problematic jacks, but the issue remained. One device is a VoIP phone base station that displays Ethernet connectivity when plugged in, yet it still lacks an IP address. This occurs with various devices—APs, phones, Windows computers—as well as their ethernet setup. For their network, the friend uses a FritzBox router with Ethernet connections to two switches, and all internal jacks are routed through those switches. The affected jacks appear to be connected on more than one switch. What could explain this behavior, and how might it be resolved?
Have you restarted the Fritzbox and switches? What are the models of the switches? If you suspect an issue with the switches, connect the Ethernet directly to the Fritzbox and check the cable. If it functions properly, the switch may need replacement. Look at the exposed Ethernet connections for any damage. Loops or sharp bends can lead to significant wear on the cable.
I restarted both the switches and the FritzBox, yet the issue continues. Linking straight to the FritzBox and switches functions correctly, giving me an IP address.
It seems there may be an issue with the internal Ethernet connections or the connectors at either end. My method would involve carefully examining the connections in the affected runs for exposed twisted pairs or poorly punched-down pairs at the keystones. Swap them out as needed and confirm that both ends use the same termination standard. If certain runs aren’t installed inside walls, look for stripped insulation or damaged wiring in those sections. Ensure no part of the cable is caught on a nail or is being forced too tightly by U-shaped fasteners. Cables placed outside a building or in crawl spaces can be damaged by animals, so verify those areas as well if relevant.