One-trick solution! A complete guide to quickly troubleshoot network IP conflicts

IP conflict refers to the use of the same IP address by two or more devices in the same subnet, which leads to communication confusion, disconnection or connection interruption. It is a common pain point in network management.

When a conflict occurs, the relevant devices usually generate alarms in the system log or router/switch (such as DHCP conflict log). Network administrators need to quickly locate the source of the conflict and restore normal access.

Common causes of IP conflicts
Static IP configuration error: manually configuring the same IP for multiple devices without proper registration management.
DHCP service abnormality: improper DHCP server configuration or lease table abnormality, repeatedly assigning the same address.
ARP spoofing or malicious attack: malicious devices disguise themselves as the IP of other devices and broadcast false ARP information to the network.
Network device failure or cache failure: The router/switch ARP cache is not updated in time, resulting in interference from old records.
IP conflict troubleshooting steps
After the core switch executes the command, the switch displays information, and the conflicting MAC, port, and other information can be found.



If the conflicting port is the downlink access switch, you need to execute dis mac-add conflicting MAC for further confirmation.

The switch closes the conflicting port. From the above conflict information, we know that G1/0/1 is the conflicting port.

Common commands for Huawei switches