3com 5500-SI Manual De Usuario
148
C
HAPTER
11: DHCP R
ELAY
C
ONFIGURATION
Actually, a DHCP relay enables DHCP clients and DHCP servers on different networks
to communicate with each other by forwarding the DHCP broadcasting packets
transparently between them.
to communicate with each other by forwarding the DHCP broadcasting packets
transparently between them.
DHCP Relay
Configuration
Configuration
If a switch belongs to a fabric, you need to enable the UDP-helper function on it
before configure it to be a DHCP relay.
before configure it to be a DHCP relay.
DHCP Relay
Configuration Tasks
Enabling DHCP
Be sure to enable DHCP before you perform other DHCP relay-related configuration,
for other DHCP-related configurations cannot take effect with DHCP disabled.
for other DHCP-related configurations cannot take effect with DHCP disabled.
Configuring an Interface
to Operate in DHCP
Relay Mode
There may be multiple DHCP servers deployed in one network. This increases the
reliability. Here, you can configure a DHCP server group containing one or multiple
DHCP servers.
reliability. Here, you can configure a DHCP server group containing one or multiple
DHCP servers.
You can configure an interface to forward DHCP packets received from DHCP clients
to a group of external DHCP server(s), so that the DHCP server(s) in this group can
assign IP addresses to the DHCP clients under this interface.
to a group of external DHCP server(s), so that the DHCP server(s) in this group can
assign IP addresses to the DHCP clients under this interface.
You can configure up to eight external DHCP IP addresses in a DHCP server group.
You can map multiple VLAN interfaces to one DHCP server group. But one VLAN
interface can be mapped to only one DHCP server group. If you execute the
dhcp-server groupNo command repeatedly, the new configuration overwrites the
previous one.
interface can be mapped to only one DHCP server group. If you execute the
dhcp-server groupNo command repeatedly, the new configuration overwrites the
previous one.
Table 133 DHCP relay configuration tasks
Operation
Description
Related section
Enable DHCP
Required
Configure an interface to
operate in DHCP relay mode
operate in DHCP relay mode
Required
Configure DHCP relay security
Required
Table 134 Enable DHCP
Operation
Command
Description
Enter system view
system-view
-
Enable DHCP
dhcp enable
Required
By default, DHCP is disabled.
By default, DHCP is disabled.
Table 135 Configure an interface to operate in DHCP relay mode
Operation
Command
Description
Enter system view
system-view
-
Configure the DHCP server
IP address(es) in a specified
DHCP server group
IP address(es) in a specified
DHCP server group
dhcp-server groupNo
ip ip-address1 [
ipaddress-list ]
ip ip-address1 [
ipaddress-list ]
Required
By default, no DHCP server IP address is
configured in a DHCP server group.
By default, no DHCP server IP address is
configured in a DHCP server group.
Map an interface to a
DHCP server group
DHCP server group
interface interface-type
interface-number
interface-number
Required
By default, a VLAN interface is not mapped
to any DHCP server group.
By default, a VLAN interface is not mapped
to any DHCP server group.
dhcp-server groupNo