What Does IPConfig/Renew Accomplish?

By Micah McDunnigan

Renewing a DHCP lease can solve many common networking issues.
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Routers can automatically add computers to their network with the Dynamic Host Configuration Protocol. The DHCP server runs on your company's router, and each of your computers have DHCP clients that communicate with the DHCP server. Entering "ipconfig/renew" into the command line tells your computer to renew its current IP address lease with the router.

Windows IP Configuration

IPConfig is Window's command line application for managing your computer's network interfaces. Typing "ipconfig" into the command line will produce a list of your network connections, their respective statuses and IP addresses. This gives you all of your basic networking information in a more succinct form than you'll find with GUI tools. You can also append a variety of commands to IPConfig, including the flag to renew your computer's IP lease.

IP Addresses

The Internet at large sees your Internet connection's IP address, but your router sees your computer through a unique address the device gave specifically to your machine. Web servers get data to your computer by sending it first to your router through your connection's IP address, and then the router forwards the data to your computer's local IP address.

Address Leases

Just as businesses lease office space and occupy it for the duration of the lease, routers lease IP addresses to individual computers. Real estate leases are only valid for a set amount of time, and so too IP address leases are only valid for a set amount of time. Once a computer's lease on a particular IP address expires, the router will not let that computer connect to its network.

Renewing IP Leases

Expired IP addresses or other issues with a computer's current IP address lease are often the reason for network connectivity issues. When you type "ipconfig /renew" into the command line, that command orders your DHCP client to renegotiate an IP address lease with the DHCP server on your router. This will either renew your current local IP address with the router or get your computer a new local IP address if the router hasn't already re-assigned the current address.