HP-UX IP Address and Client Management Administrator's Guide HP-UX 11i v2, HP-UX 11i v3

Figure 1-4 When Client and Server Are on the Same Link
The client and the server communicate with each other by exchanging packets as follows (see
the numbers 1,2,3,4, and 5 in Figure 1-4):
1. The client sends a DHCP SOLICIT message to the ALL DHCP Agents address (FF02::1:2)
to locate suitable servers.
2. Multiple servers respond to the SOLICIT message by sending a DHCP ADVERTISE message
to the client.
3. The client sends a DHCP REQUEST message to the DHCPv6 server that has the highest
preference value.
4. The server responds to the client’s message by sending a DHCP REPLY message. The DHCP
REPLY message contains the IPv6 address and configuration parameters required by the
client.
The server sends the DHCP REPLY message to respond to the client’s REQUEST, RENEW,
REBIND, RELEASE, RECONFIGURE, CONFIRM, and INFORMATION REQUEST messages.
5. The client sends a DHCP RELEASE message to return one or more IPv6 addresses to the
server when it has completed using an IPv6 address.
See “Message Types” (page 50) for more information about message types.
DHCPv6 requires relays to be set up on the client’s link when the client and the server are on
different links. Relays receive messages from the client and forward them verbatim to a set of
servers that the DHCP domain includes. Relays forward the client’s messages to servers using
any of the following addresses:
• All DHCP Servers Site-local multicast address
• Other site-local multicast addresses set up within the DHCP domain to include the servers
in that domain
• A list of unicast addresses for servers
Figure 1-5 depicts how the client and the server, on different links, communicate with each other.
Figure 1-5 When Client and Server Are on Different Links
The client and the server exchange messages with each other via a relay as follows (see numbers
1,2,3,4, and 5 in Figure 1-5):
DHCPv6 Overview 49