Introduction: The server includes options the server will return to the client in a subsequent Reply message. The information in these options may be used by the client in the selection of a server if the client receives more than one Advertise message. If the client has included an Option Request option in the Solicit message ...
The server MAY add a Preference option to carry the preference value
for the Advertise message. The server implementation SHOULD allow
the setting of a server preference value by the administrator. The
server preference value MUST default to zero unless otherwise
configured by the server administrator.
The server includes a Reconfigure Accept option if the server wants
to require that the client accept Reconfigure messages.
The server includes options the server will return to the client in a
subsequent Reply message. The information in these options may be
used by the client in the selection of a server if the client
receives more than one Advertise message. If the client has included
an Option Request option in the Solicit message, the server includes
options in the Advertise message containing configuration parameters
for all of the options identified in the Option Request option that
the server has been configured to return to the client. The server
MAY return additional options to the client if it has been configured
to do so. The server must be aware of the recommendations on packet
sizes and the use of fragmentation in section 5 of RFC 2460.
If the Solicit message from the client included one or more IA
options, the server MUST include IA options in the Advertise message
containing any addresses that would be assigned to IAs contained in
the Solicit message from the client. If the client has included
addresses in the IAs in the Solicit message, the server uses those
addresses as hints about the addresses the client would like to
receive.
If the server will not assign any addresses to any IAs in a
subsequent Request from the client, the server MUST send an Advertise
message to the client that includes only a Status Code option with
code NoAddrsAvail and a status message for the user, a Server
Identifier option with the server's DUID, and a Client Identifier
option with the client's DUID.
If the Solicit message was received directly by the server, the
server unicasts the Advertise message directly to the client using
the address in the source address field from the IP datagram in which
the Solicit message was received. The Advertise message MUST be
unicast on the link from which the Solicit message was received.
If the Solicit message was received in a Relay-forward message, the
server
