An IP address conflict occurs when two computers connected to a Local Area Network (LAN) or the Internet are assigned the same IP address. When this happens, the network interface on systems becomes disabled, causing each system to lose connectivity until the conflict is resolved. Some of the reasons for this common network issue include the BYOD phenomenon, DHCP servers and their configuration, and human errors that occur during manual IP address management.
Resolving IP Conflicts in Your Network
The first and foremost step in resolving IP conflicts is to locate the systems that are in conflict. Administrators often locate these conflicting systems using ping/ARP commands or tracking tools. In networks where IP addresses are statically assigned, the system administrator has to manually locate and change the IP address of the system in conflict. However, in dynamic IP distribution environments, systems issue repeated requests for valid addresses, enabling IP conflicts to eventually resolve themselves. But, this might not always be the case.
- Static IP – If IP addresses are manually assigned to computers in your network, the following steps will help you change the IP address of the system.
- Right-click "Network Neighborhood" on your desktop. If you have Windows Vista or Windows 7 and Windows 8, right click on your network card and choose “Open Network and Sharing Center”.
- Select "Local Area Connection" Or “Ethernet” and then click on "Properties."
- Click "TCP/IP" in the list of protocols. Click the "Properties" button underneath the list of protocols. Enter a new IP address in the opened window. Click "OK" to confirm your settings.
- Dynamic IP - If IP addresses are distributed dynamically by a DHCP server, one way to fix the conflict is by manually entering IPCONFIG/RELEASE and IPCONFIG/RENEW from the command prompt.
- Open the command prompt by clicking "Start" and typing "cmd" into the search field.
- Type "Ipconfig/release" at the "C:" prompt and then press "Enter." The results of the IP release process are displayed under "Windows IP Configuration." The prompt re-appears at the end of the results when the process is complete.
- Type "ipconfig/renew" at the prompt and then press "Enter." This command automatically assigns your computer a new available IP address.
Tips to Avoid IP Conflicts
- In networks where IP addresses are statically assigned, be careful to ensure each device is configured with a unique IP address.
- Confirm that your DHCP servers are configured properly so that there is no duplication in assignment of IP addresses.
- To avoid DHCP malfunction, ensure that the firmware on the DHCP servers are up to date.
- Set up a mechanism to be notified of IP conflicts in the network so that you are aware of the issue and take proactive action before any users call in to support.
There are also automated systems that make these steps much faster and easier. Learn more about automating your IP address management tasks with SolarWinds IP Address Manager.