MES53xx, MES33xx, MES23xx Ethernet Switch Series 159
Privileged EXEC mode commands
Command line prompt in the Privileged EXEC mode is as follows:
console#
Table 5.173. Privileged EXEC mode commands
show dot1x interface
{gigabitethernet gi_port |
tengigabitethernet te_port |
fortygigabitethernet fo_port |
oob}
show dot1x statistics
interface
{gigabitethernet gi_port |
tengigabitethernet te_port |
fortygigabitethernet fo_port |
oob}
11.1.3 DHCP management and Option 82
DHCP (Dynamic Host Configuration Protocol) is a network protocol that allows the client to request
IP address and other parameters required for the proper operations in a TCP/IP network.
DHCP is used by hackers to attack devices from the client side, forcing DHCP server to report all
available addresses, and from the server side by spoofing. The switch firmware features the DHCP
snooping function that ensures device protection from attacks via DHCP.
The device discovers DHCP servers in the network and allows them to be used only via trusted
interfaces. The device also controls client access to DHCP servers using a mapping table.
DHCP Option 82 is used to inform DHCP server about the DHCP Relay Agent and the port a
particular request came from. It is used to establish mapping between IP addresses and switch ports and
ensure protection from attacks via DHCP. Option 82 contains additional information (device name, port
number) added by the switch in a DHCP Relay agent mode in the form of a DHCP request received from
the client. According to this option, DHCP server provides an IP address (IP address range) and other
parameters to the switch port. When the necessary data is received from the server, the DHCP Relay
agent provides an IP address and sends other required data to the client.
Table 5.174. Option 82 field format