Skip to content

Symptoms: Server Cabled to Wrong Switch Port / Wrong VLAN

  • A newly racked server (srv-prod-55) was cabled and powered on, but it cannot reach its expected network gateway.
  • The server's primary NIC has an IP address via DHCP, but it received 172.16.50.x instead of the expected 10.30.20.x.
  • The server can ping other hosts on 172.16.50.0/24 but cannot reach anything on 10.30.20.0/24.
  • The network team confirms 172.16.50.0/24 is the development VLAN (VLAN 50), not production VLAN 320.
  • The server was supposed to be cabled to ToR switch port Eth1/33 (VLAN 320) per the cabling plan.
  • LLDP output on the server shows it is connected to a different switch port than expected.
  • The cabling was done by a contractor during an overnight shift with limited supervision.
  • The cable label matches the expected port, but the physical cable goes to a different port.
  • Other servers in the same rack are on the correct VLANs; only srv-prod-55 is wrong.