IP address conflict in DHCP protocol troubleshooting

I am not sure whether you have mastered the essence of this series of articles about DHCP troubleshooting. Some friends may still be confused. Next, let's list the DHCP protocol Fault Handling Cases to help you analyze them.

The IP address obtained by the client from the DHCP server conflicts with the IP address of other hosts.

DHCP protocol troubleshooting ◆ Network Environment

When the client obtains an IP address from the DHCP server, it finds that an IP address conflict occurs. Shows the networking environment.

Figure conflict between IP addresses obtained through DHCP

DHCP protocol troubleshooting ◆ Fault Analysis

A user on the network may have configured the same IP address as the IP address assigned by the DHCP server for a host without authorization, resulting in a conflict.

DHCP protocol troubleshooting ◆ operation steps

1. Disable the NIC of the client computer, and ping the host on another host to check whether the IP address already exists in the network.

2. If you can receive a response message from the ping operation, it indicates that the IP address has been statically configured by another user.

3. Enable the client nic. in Windows 98, run winipcfg, release the dynamic IP address, and apply for a dynamic IP address again. In Windows XP, win2000, or DOS, you can use the ipconfig/release command to release the dynamic IP address and use the ipconfig/renew command to apply for a new dynamic IP address.

DHCP protocol troubleshooting ◆ task example

After completing the preceding operations, the client applies for an IP address and resolves the fault.

DHCP protocol troubleshooting ◆ case summary

IP address conflicts are common in the network and cannot be easily avoided. Generally, other users on the network have configured the same IP address statically.

In case of IP address conflict, the client needs to execute the ipconfig/release command to release the IP address, and then run the ipconfig/renew command to re-apply for an IP address. During the re-application process, the server will first assign the IP address in the original conflict, but ICMP will detect the conflict and add the IP address to the conflicting linked list. The IP address will not be allocated within one hour. The server then assigns a new IP address to the client.