3Com SuperStack 4 Configuration Manual page 88

100 C 5: N
HAPTER ETWORK
Troubleshooting DHCP
Relay Configuration
P O
ROTOCOL PERATION
Networking Diagram
Figure 25 Networking Diagram of Configuration DHCP Relay
DHCP client
10.110.0.0
Ethernet
Switch ( DHCP Relay )
Configuration Procedure
1 Configure the group number of DHCP Server as 1 and the IP address as
202.38.1.2.
[SW5500]dhcp-server 1 ip 202.38.1.2
2 Associate the VLAN interface 2 with DHCP Server group 1.
[SW5500]interface vlan 2
[SW5500-Vlan-interface2]dhcp-server 1
3 Configure the IP address of the VLAN interface 2, which must be in the same
segment as DCHP Client.
[SW5500-Vlan-interface2]ip address 10.110.1.1 255.255.0.0
To allocate an IP address successfully for the DHCP Client, you need to make the
necessary configuration on the DHCP Server, which varies, depending on device
type.
Perform the following procedure if a user cannot apply for an IP address
dynamically:
1 Use the
display dhcp-server
the corresponding DHCP Server has been configured.
2 Use the
display vlan
to check if the VLAN and the corresponding interface IP address have been
configured.
3 Ping the configured DHCP Server to ensure that the link is connected.
4 Ping the IP address of the VLAN interface of the Switch to which the DHCP user is
connected from the DHCP Server to make sure that the DHCP Server can correctly
find the route of the network segment the user is on. If the ping execution fails,
check if the default gateway of the DHCP Server has been configured as the
address of the VLAN interface that it locates on.
If there is no problem found in the last two steps, use the
command to view which packet has been received. If you only see the
groupNo
Discover packet and there is no response packet, the DHCP Server has not sent the
message to the Ethernet Switch. In this case, check if the DHCP Server has been
configured properly. If the numbers of request and response packets are normal,
DHCP client
10.110.1.1
Internet
command to check if the IP address of
groupNo
and
display ip interface vlan-interface
DHCP Server
202.38.1.2
202.38.1.1
Ethernet
202.38.0.0
display dhcp-server
commands