R Elay - Black Box LPB2910A User Manual

2-­‐4.3 R elay
A D HCP r elay a gent i s u sed t o f orward a nd t o t ransfer D HCP m essages b etween t he c lients a nd t he
server w hen t hey a re n ot i n t he s ame s ubnet d omain. I t s tores t he i ncoming i nterface I P a ddress i n
the G IADDR f ield o f t he D HCP p acket. T he D HCP s erver c an u se t he v alue o f G IADDR f ield t o
determine t he a ssigned s ubnet. F or s uch c onditions, p lease m ake s ure t he s witch c onfiguration o f
VLAN i nterface I P a ddress a nd P VID ( Port V LAN I D) a re c orrect.
Web I nterface
To c onfigure D HCP R elay i n t he w eb i nterface:
1. Click C onfiguration, D HCP, R elay.
2. Specify t he R elay M ode, R elay s erver, R elay I nformation M ode, R elay I nformation P olicy.
3. Click A pply.
Figure 2 -­‐4.3: The D HCP R elay C onfiguration
Parameter d escription:
Relay M ode:

Indicates t he D HCP r elay m ode o peration.
Possible m odes a re:
Enabled: Enable DHCP relay mode operation. When DHCP relay mode operation is enabled, the
agent forwards and transfers DHCP messages between the clients and the server when they are
not in the same subnet domain. The DHCP broadcast message won't be flooded for security
considerations.
Disabled: D isable D HCP r elay m ode o peration.
Relay S erver

Indicates t he D HCP r elay s erver I P a ddress.
Relay I nformation M ode

Indicates the DHCP relay information mode option operation. The option 82 circuit ID format is
"[vlan_id][module_id][port_no]". The first four characters represent the VLAN ID, the fifth and
sixth c haracters a re t he m odule I D ( in a s tandalone d evice i t a lways e quals 0 , i n s tackable d evice i t
means switch ID), and the last two characters are the port number. For example, "00030108"
means t he D HCP m essage i s r eceived f rom V LAN I D 3 , s witch I D 1 , p ort N o 8 . T he o ption 8 2 r emote
ID v alue e quals t he s witch M AC a ddress.
Possible m odes a re:
Enabled: Enable DHCP relay information mode operation. When DHCP relay information mode
operation i s e nabled, t he a gent i nserts s pecific i nformation ( option 8 2) i nto a D HCP m essage w hen
forwarding to a DHCP server and removes it from a DHCP message when transferring to a DHCP
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Publication date: Sept, 2015
Revision A1