mac

Commands for DHCP Snooping
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31.27 ip dhcp snooping trust
Command: ip dhcp snooping trust
no ip dhcp snooping trust
Function: Set or delete the DHCP Snooping trust attributes of a port.
Parameters: None
Command Mode: Port mode
Default Settings: By default, all ports are non-trusted ports
Usage Guide: Only when DHCP Snooping is globally enabled, can this command be set.
When a port turns into a trusted port from a non-trusted port, the original defense action
of the port will be automatically deleted; all the security history records will be cleared
(except the information in system log).
Example: Set port ethernet1/1 as a DHCP Snooping trusted port
switch(config)#interface ethernet 1/1
switch(Config- Ethernet 1/1)#ip dhcp snooping trust
31.28 ip user helper-address
Command: ip user helper-address <svr_addr> [port <udp_port>] source <src_addr>
[secondary]
no ip user helper-address [secondary]
Function: Set the address and port of HELPER SERVER.
Parameters:
<svr_addr>: The IP address of HELPER SERVER IP in dotted-decimal notation.
udp_port: The UDP port of HELPER SERVER, the range of which is1－65535,
and its default value is 9119.
src_addr: The local management IP address of the switch, in dotted-decimal
notation.
sencondary: Whether it is a secondary SERVER address.
Command Mode: Global mode
Default Settings: There is no HELPER SERVER address by default.
Usage Guide: DHCP SNOOPING will send the monitored binding information to
HELPER SERVER to save it. If the switch starts abnormally, it can recover the binding
data from HELPER SERVER. The HELPER SERVER function usually is integrated into
DCBI packet. The DHCP SNOOPING and HELPER SERVER use the UDP protocol to
communicate, and guarantee the arrival of retransmitted data. HELPER SERVER
configuration can also be used to sent DOT1X user data from the server, the detail of