Allied Telesis AT-8100 Series - Manual (Page 485)

AT-8100 Switch Command Line User’s Guide
485
The possible actions are listed here:
 Leave the existing option-82 field untouched
 Append its own option-82 field after the existing field
 Drop the packet
 Replace the existing option-82 information with its own (the default)
DHCP Relay
Agent Option 82
Maximum
Message Length
When a DHCP relay agent (that has the option 82 insertion enabled)
receives a request packet from a DHCP client, it appends the option 82
component data and forwards the packet to the DHCP server. The DHCP
client sometimes issues packets containing pad option fields that can be
overwritten with option 82 data. Where there are insufficient pad option
fields to contain all the option 82 data, the DHCP relay increases the
packet size to accommodate the option 82 data. If the new (increased)
packet size exceeds a defined maximum length, the DHCP relay will drop
the packet. To set the maximum packet length, refer to “Configuring the
DHCP Relay Option 82” on page 489.