How IP Address Conflicts HappenTwo computers can acquire conflicting IP addresses in any of several ways:
- A system administrator assigns two computers on the LAN the same static IP address
- A system administrator assigns a computer a static IP address within the local network's DHCP range (dynamic IP range), and the same address is automatically assigned by the local DHCP server.
- A malfunction in the network's DHCP server allows the same dynamic address to automatically be assigned to multiple computers.
- An Internet Service Provider (ISP) accidentally assigns two customers the same IP address (either statically or dynamically).
- A mobile computer is put into standby / hibernate mode and then awakened later.
Recognizing IP Address ConflictsOn most Microsoft Windows computers, if you attempt to set a fixed (static) IP address that is already active on the local network, you will receive the following pop-up error message:
The static IP address that was just configured is already in use on the network. Please reconfigure a different IP address.
On newer Microsoft Windows computers having dynamic IP conflicts, you should receive a balloon error message in the Taskbar as soon as the operating system detects the issue:
There is an IP address conflict with another system on the network.
Sometimes, especially on older Windows computers, a message similar to the following may instead appear in a pop-up window:
The system has detected a conflict for IP address...
Resolving IP Address ConflictsTry the following remedies for IP conflicts:
1. For networks where IP addresses are fixed (statically assigned), ensure each local host is configured with a unique IP address.
2. If your computer has a dynamically assigned address, releasing and renewing its IP address can work around IP address conflicts. See also - How to Release / Renew IP Addresses on Windows
3. If your home router is believed to have a faulty DHCP server causing IP conflicts on the home network, upgrading the router firmware may resolve this problem.