Releasing and Renewing DHCP Settings

DHCP servers can assign many network configuration settings automatically. These include IP addresses, default gateways, primary and secondary DNS servers, primary and secondary WINS servers, and more. When computers use dynamic addressing, they are assigned a lease on a specific IP address. This lease is good for a specific time period and must be renewed periodically. When the lease needs to be renewed, the computer contacts the DHCP server that provided the lease. If the server is available, the lease is renewed and a new lease period is granted. You can also renew leases manually as necessary on individual computers or by using the DHCP server itself.

Problems can occur during the lease assignment and renewal process that prevent network communications. If the server isn't available and cannot be reached before a lease expires, the IP address can become invalid. If this happens, the computer might use the alternate IP address configuration to set an alternate address, which in most cases has settings that are inappropriate and prevent proper communications. To resolve this problem, you'll need to release and then renew the DHCP lease.

Another type of problem occurs when users move around to various offices and subnets within the organization. Although moving from location to location, their computers might obtain DHCP settings from the wrong server. When the users return to their offices, the computers might seem sluggish or perform incorrectly due to the settings assigned by the DHCP server at another location. If this happens, you'll need to release and then renew the DHCP lease.

You can use the graphical interface to release and renew DHCP leases by completing the following tasks:

1. Click Start and then click Network. In Network Explorer, click Network And Sharing Center on the toolbar.
2. In Network And Sharing Center, click Manage Network Connections.
3. In Network Connections, right-click the connection you want to work with and then click Diagnose.
4. After Windows Network Diagnostics tries to identify the problem, a list of possible solutions is provided. If the computer has one or more dynamically assigned IP addresses, one of the solutions should be Automatically Get New IP Settings. Click this option.

You can also follow these steps to use the IPCONFIG command to renew and release settings:

1. Start an elevated command prompt.
2. To release the current settings for all network adapters, type ipconfig/release at the command line. Then renew the lease by typing ipconfig/renew.
3. To only renew a DHCP lease for all network adapters, type ipconfig/renew at the command line.
4. You can check the updated settings by typing ipconfig/all at the command line.

If a computer has multiple network adapters and you only want to work with one or a subset of the adapters, you can do this by specifying all or part of the connection name after the ipconfig/renew or ipconfig/release command. Use the asterisk as a wildcard character to match any characters in a connection's name. For example, if you wanted to renew the lease for all connections with names starting with Loc, you could type the command ipconfig/renew Loc*. If you wanted to release the settings for all connections containing the word Network, you could type the command ipconfig/release *Network*.