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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
19.28 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
usage is described in the chapter of dot1x configuration.
Two HELPER SERVER addresses are allowed, DHCP SNOOPING will try to connect
to PRIMARY SERVER in the first place. Only when the PRIMARY SERVER is
unreachable, will the switch c HELPER SERVER connects to SECONDARY SERVER.
Please pay attention: source address is the effective management IP address of the
switch, if the management IP address of the switch changes, this configuration should be
updated in time.
Example: Set the local management IP address as 100.1.1.1, primary HELPER SERVER