User Manual
UMN:CLI
V8102
433
There is the four-message exchange handshake for a single interface with one IA_NA
and one address for this IA_NA.
To obtain an IP address, the DHCP client daemon (dhcpcd6) sends a Solicit message to
the link-scoped address (FF02::1:2), which is received by the server and processed. If a
free address is available for that client, an Advertise message is created and sent back to
the client. This message contains an IP address and other options that are appropriate for
that client. The client receives the server DHCP Advertise message and stores it while
waiting for other advertisements. When the client has chosen the best advertisement, it
sends a DHCP Request to the link-scoped address (FF02::1:2) specifying which server
advertisement it wants.
All configured DHCP servers receive the Request message. Each monitors to see if it is
the requested server. The server does not process any packet with a server DUID that
does not match its own. The requested server marks the address as assigned and re-
turns a DHCP Reply, at which time, the transaction is complete. The client has an ad-
dress for the period of time (valid-lifetime) designated by the server.
When the preferred-lifetime expires for the address, the client sends the server a Renew
message to extend the lease time. If the server is willing to renew the address, it sends a
DHCP Reply message. If the client does not get a response from the server that owns its
current address, it multicasts a DHCP Rebind message if, for example, the server has
been moved from one network to another. If the client has not renewed its address after
the valid-lifetime, the address is removed from the interface and the process starts over.
This cycle prevents multiple clients on a network from being assigned the same address.
9.7.1
DHCPv6 Server
9.7.1.1
Creating DHCPv6 address Pool
The DHCP pool is a group of IP addresses that will be assigned to DHCP clients by
DHCP server. You can create various DHCP pools that can be configured with a different
network, default gateway and range of IP addresses. This allows the network administra-
tors to effectively handle multiple DHCP environments.
To create a DHCPv6 pool, use the following command.
Command
Mode
Description
ipv6 dhcp pool
POOLNAME
Global
Creates a DHCPv6 pool and opens
DHCPv6 Pool
Configuration
mode.
no ipv6 dhcp pool
POOLNAME
Removes the specified DHCPv6 pool.
The following is an example of creating the DHCPv6 pool as
sample
.
SWITCH(config)#
ipv6 dhcp pool
sample
SWITCH(config-dhcp6[sample])#
