What are the possible reasons for the failure of DHCP in a network..?

Hello,

Possible reasons for DHCP failure

Check the client computer has a valid functioning network connection

Check the DHCP server is reachable from the client through PING

Configure a scope to match the network address of its client

Make sure there is only one logical route between the DHCP server and the remote clients

Make sure that multiple DHCP servers on the same LAN are not configured with overlapping scopes.

Verify that TCP/IP filter on the router is not blocking DHCP traffic. DHCP traffic uses the UDP ports of67 and68.

Check out the DHCP scope network and DHCP network range....also if you enabled dhcp for too many networks checkout the gateways ip... DHCP ip rnage and scope range should be in same range then only dhcp able to service ip to clients...

check the dhcp scope range  it possible that number of IP not enough for all devices

Make sure your firewall allows UDP ports67 and68 (request and assign). If those are blocked by a firelwall between your DHCP server(s) and the hosts in your network, then only APIPA will be assigned by the client OSs.

CHECK THE SCOPE .IF THIS  HAVE AVAILABLE IP ADDRESS OR NOT. AND MAKE SURE THAT U MAY CONFIGURE RELAY AGENT PROPERLY.

Possible Cause of Problem (1)

The IP address of the DHCP server was changed, and now DHCP clients cannot get IP addresses.

Resolution of Problem (1)

A DHCP server can only service requests for a scope that has a network ID that is the same as the network ID of its IP address.

Ensure that the DHCP server’s IP address is configured correctly. Verify that all IP helpers on routers and DHCP relay agents accurately refer to this IP address.

Possible Cause of Problem (2)

The DHCP clients are located across a router or switch from the subnet where the DHCP server resides and are unable to receive an address from the server.

Resolution of Problem (2)

A DHCP server can provide IP addresses to client computers on remote multiple subnets only if the router or switch that separates them can act as a BOOTP Relay.

Completing the following steps might correct this problem:

1.     Configure a BOOTP Relay on the client subnet (that is, the same physical network segment). Use the network vendor prescription for configuring the BOOTP Relay.

2.     At the DHCP server, do the following:

a.     Configure a scope to match the network address on the other side of the router or switch where the affected clients are located.

b.    In the scope, make sure that the subnet mask is correct for the remote subnet.

c.     Use a default gateway on the network connection of the DHCP server in such a way that it is not using the same IP address as the switch or router that supports the remote subnet where the clients are located.

d.    Do not include this scope (that is, the one for the remote subnet) in superscopes configured for use on the same local subnet or segment where the DHCP server resides.

e.     Make sure there is only one logical route between the DHCP server and the remote subnet clients.

Possible Cause of Problem (3)

Multiple DHCP servers exist on the same LAN.

Resolution of Problem (3)

Make sure that multiple DHCP servers on the same LAN are not configured with overlapping scopes.