3com 4210 PWR 9-Port 3CR17341-91-ME User Manual

Product codes
3CR17341-91-ME
Page of 567
288
C
HAPTER
 26: DHCP/BOOTP C
LIENT
 C
ONFIGURATION
n
Currently, the Switch 4210 functioning as the DHCP client can use an IP address 
for 24 days at most. That is, the DHCP client can obtain an address lease for no 
more than 24 days even though the DHCP server offers a longer lease period.
n
To improve security and avoid malicious attack to the unused SOCKETs, the Switch 
4210 provides the following functions:
UDP 67 and UDP 68 ports used by DHCP are enabled only when DHCP is 
enabled. 
UDP 67 and UDP 68 ports are disabled when DHCP is disabled. 
The specific implementation is:
Using the ip address dhcp-alloc command enables the DHCP client, and UDP 
port 68.
Using the undo ip address dhcp-alloc command disables the DHCP client, and 
UDP port 68.
Displaying 
DHCP/BOOTP Client 
Configuration
DHCP Client 
Configuration 
Example
Network requirements
Using DHCP, VLAN-interface 1 of Switch B is connected to the LAN to obtain an IP 
address from the DHCP server.
Configure the VLAN interface to 
obtain IP address through DHCP 
or BOOTP
ip address { bootp-alloc 
dhcp-alloc }
Required
By default, no IP address is 
configured for the VLAN 
interface.
Table 215   Configure a DHCP/BOOTP client
Operation
Command
Description
Operation
Command
Description
Display related information on a 
DHCP client
display dhcp client [ verbose 
]
Optional
Available in any view
Display related information on a 
BOOTP client
display bootp client [ 
interface Vlan-interface 
vlan-id ]