Option 82
configuration
DHCP client request packet inbound to the routing switch
Packet has
no Option 82
field
Packet includes an Option 82 field
Append
Append an
Option 82 field
Append
allows the most detail in defining DHCP policy boundaries. For example,
where the path from a client to the DHCP Option 82 server includes multiple
relay agents with Option 82 capability, each relay agent can define a DHCP
policy boundary and append its own Option 82 field to the client request
packet. The server can then determine in detail the agent hops the packet
took, and can be configured with a policy appropriate for any policy boundary
on the path.
NOTE:
In networks with multiple relay agents between a client
and an Option 82 server,
append
can be used only if the
server supports multiple Option 82 fields in a client request. If
the server supports only one Option 82 field in a request,
consider using the
keep
option.
Keep
Append an
Option 82 field
If the relay agent receives a client request that already has one or more
Option 82 fields,
keep
causes the relay agent to retain such fields and
forward the request without adding another Option 82 field. But if the
incoming client request does not already have any Option 82 fields, the relay
agent appends an Option 82 field before forwarding the request. Some
applications for
keep
include:
• The DHCP server does not support multiple Option 82 packets in a client
request, and there are multiple Option 82 relay agents in the path to the
server.
• The unusual case where DHCP clients in the network add their own
Option 82 fields to their request packets, and you do not want any
additional fields added by relay agents.
This policy does not include the
validate
option (described in the next
section) and allows forwarding of all server response packets arriving
inbound on the routing switch (except those without a primary relay agent
identifier.)
Table Continued
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Aruba 3810 / 5400R Multicast and Routing Guide for ArubaOS-
Switch 16.08
