Networking Tips: Understanding and Resolving IP Address Conflicts Finding and Fixing the Culprit Joseph Moran
Finding and Fixing the Culprit
As we mentioned above, IP conflicts tend to eventually work themselves out in DHCP environments because systems issue repeated requests for valid addresses. But since the process can take awhile and doesn't always work as planned, one way to hasten a fix is by manually entering IPCONFIG /RELEASE and IPCONFIG /RENEW from a command prompt — restarting a system accomplishes the same thing but takes a lot longer.
If the conflict persists even after renewing the IP address, it may be because your system's been re-issued the same address it already had and another system on your network is the source of the problem. You can get a clue about the offender by checking the System Log within the Windows Event Viewer (which you can get to via Start|Control Panel| Administrative Tools|Event Viewer) and looking for a DHCP error entry.
The entry will list a network address (actually a MAC address) that you can use to identify the conflicting device, either by running IPCONFIG / ALL on a Windows system or by checking the label on the back or underside of a non-PC device.
Performing a IPCONFIG release and renew or restarting the other device should set things right. If not, restarting your router should do the trick as it will reset the DHCP server and force all systems to request new IP addresses.
If you experience chronic IP conflicts with no apparent cause, you may want to consider updating your router with its most recent firmware. If you're already running the latest firmware, re-flashing the router with the same firmware, in rare cases, can make its DHCP server more reliable.
Joe Moran is a regular contributor to PracticallyNetworked.
