DHCP Scope Exceptions

ID: Q133214

The information in this article applies to:

SYMPTOMS

Clients on your network may not be able to obtain leases from your Dynamic Host Configuration Protocol (DHCP) Server.


CAUSE

This behavior can occur if your scope is configured to lease the first and last addresses for a subnet.


RESOLUTION

To resolve this behavior, check your scope to make sure it is not trying to lease the first and last subnet for your subnet.


MORE INFORMATION

If you are using 100.25.1.0 as your network ID, and you are using a subnet mask of 255.255.255.0, the last octet would identify your hosts. As a result, both of the following IP addresses would be invalid: 100.25.1.0 and 100.25.1.255.

However, if the host ID portion of the address has a 255, or a 0, and it is in the middle of the scope, these addresses are valid.

For example, if you are using 100.25.0.0 as your scope, and the subnet mask is 255.255.0.0, the first address will be 100.25.0.0 and the last address would be 100.25.255.255. These are the only 2 illegal addresses in this range. An address of 100.25.1.255 would be valid and an address of 100.25.2.255 would also be valid.

The first and last address in a subnet are illegal and can cause irregular behavior in an environment if they were to be leased.

Additional query words: prodnt 


Keywords          : kbnetwork nttcp NTSrvWkst 
Version           : 3.5 3.51 4.0
Platform          : winnt 
Issue type        :

Last Reviewed: February 17, 1999