3Com Switch 7750 Configuration Guide

736 CHAPTER 67: UDP-HELPER CONFIGURATION
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CAUTION:
■ You need to enable the UDP-Helper function before specifying a UDP-Helper
destination port.
■ The dns, netbios-ds, netbios-ns, tacacs, tftp, and time keywords refers to
the six default UDP ports. You can configure a default port to be a UDP-Helper
destination port by specifying the corresponding port number or the
corresponding keyword. For example, udp-helper port 53 and udp-helper
port dns specify the same port as a UDP-Helper destination port.
■ The display current-configuration command does not display the default
UDP ports that are configured to be UDP-Helper destination ports.
■ After UDP-Helper is disabled, all the configured UDP ports are cancelled,
including the default ports.
■ You can configure up to 20 destination servers on a VLAN interface.
■ If the destination server is configured on a VLAN interface, the UDP broadcast
packets received from the ports in the VLAN with specific UDP-Helper
destination ports are forwarded to the destination server configured on the
VLAN interface.
Displaying and
Maintaining
UDP-Helper
After performing the above configurations, you can use the display command in
any view to display the information about the destination servers and the number
of the packets forwarded to each destination server. Verify the configuration by
checking the output information. You can use the reset command in user view to
clear statistics about packets forwarded by UDP-Helper.
Configure a UDP port as a
UDP-Helper destination port
udp-helper port { port | dns |
netbios-ds | netbios-ns |
tacacs | tftp | time }
This operation is unnecessary
if the port is among the
default UDP ports listed in
Table 591.
With UDP-Helper enabled,
UDP broadcast packets
destined for the ports listed in
Table 591 are relayed by
default.
Enter VLAN interface view interface vlan-interface
vlan-id
-
Configure the destination
server to which the matched
UDP broadcast packets are to
be forwarded
udp-helper server ip-address Required
By default, no destination
server is configured
Table 592 Configure UDP-Helper
Operation Command Description
Table 593 Display and Maintain UDP-Helper
Operation Command Description
Display the information about
the destination servers and
the number of the packets
forwarded to each destination
server
display udp-helper server
[ interface vlan-interface
vlan-id ]
You can use the display
command in any view