Dhcp Servers - Enterasys VH-2402-L3 Management Manual

DHCP Servers

The Dynamic Host Configuration Protocol (DHCP) is used to
dynamically assign a TCP/IP network configuration to
network devices and computers on the network. It also
ensures that IP address conflicts do not occur.
IP addresses are assigned from a pool of free addresses.
Each IP address assigned has a 'lease' and a 'lease
expiration period'. The lease must be periodically renewed.
If the lease is expires, the IP address is returned to the pool
of available IP addresses.
Usually, it is a network policy to assign the same IP address
to a given network device or computer each time.
If the IP address lease expires, the network device sends a
message to the DHCP server requesting a lease renewal.
The DHCP server can send an acknowledgement containing
a new lease and updated configuration information.
If an IP address lease cannot be renewed, the network
device or computer sends a request to all local DHCP
servers attempting to renew the lease. If the DHCP returns
a negative acknowledgement, the network device must
release its TCP/IP configuration and reinitialize.
When a new TCP/IP configuration is received from a DHCP
server, the network device checks for a possible IP address
conflict by sending an Address Resolution Protocol (ARP)
request that contains its new IP address.
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