By default,
S5500-SI series Ethernet switches do not forward IP broadcast packets. So, to
utilize the UDP Helper function, you need to execute the ip
forward-broadcast command in system view first. For details, refer to the IP
Address and Performance part of the manual.
Syntax
display udp-helper server [ interface interface-type interface-number ]
View
Any view
Parameter
interface interface-type
interface-number: Displays UDP relay forwarding information on the
specified interface.
Description
Use the display udp-helper server command
to display the UDP relay forwarding information on the specified interface or
all interfaces.
If interface-type interface-number is
not specified, this command displays the UDP relay forwarding information on
all the interfaces.
Example
# Display the UDP relay forwarding
information on Vlan-interface1.
<Sysname> display udp-helper
server interface Vlan-interface 1
Interface name Server address Packets
sent
Vlan-interface1 192.1.1.2 0
The information
above shows that the IP address of the destination server corresponding to
Vlan-interface1 is 192.1.1.2, and that no packets are forwarded.
Syntax
reset udp-helper packet
View
User view
Parameter
None
Description
Use the reset udp-helper packet
command to clear the statistics of packets forwarded.
Related command: display udp-helper
server.
Example
# Clear the statistics of the packets
forwarded by UDP relay.
<Sysname> reset udp-helper
packet
Syntax
udp-helper
enable
undo udp-helper enable
View
System view
Parameter
None
Description
Use the udp-helper enable command to
enable UDP Helper.
Use the undo udp-helper enable
command to disable UDP Helper.
UDP Helper is disabled by default.
Example
# Enable UDP Helper
<Sysname> system-view
[Sysname] udp-helper enable
Syntax
udp-helper port { port-number | dns | netbios-ds | netbios-ns
| tacacs | tftp | time }
undo udp-helper port { port-number | dns | netbios-ds | netbios-ns
| tacacs | tftp | time }
View
System view
Parameter
port-number: UDP port number, in the range 1 to 65535 (67 and 68 not included).
dns: Specifies
the UDP port assigned to DNS service (that is, port 53).
netbios-ds: Specifies
the UDP port assigned to NetBIOS-DS (that is, port 138) .
netbios-ns: Specifies
the UDP port assigned to NetBIOS-NS (that is, port 137).
tacacs: Specifies
the UDP port assigned to TACACS (that is, port 49).
tftp: Specifies
the UDP port assigned to TFTP (that is, port 69).
time: Specifies
the UDP port assigned to the time service (that is, port 37).
Description
Use the udp-helper port command to
specify a UDP port. With this command executed, only the UDP Helper packets
with their UDP ports being the one configured by this command are forwarded.
Use the undo udp-helper port command
to cancel the configuration.
By default, with UDP Helper function
enabled, UDP Helper packets with their UDP port numbers being 69, 53, 37, 137,
138, and 49 are forwarded. The configuration of all UDP ports (including the
default ports) is removed if you disable UDP Helper.
Example
# Configure to forward UDP Helper packets
with their UDP port being that assigned to DNS.
<Sysname> system-view
[Sysname] udp-helper enable
[Sysname] udp-helper port dns
Syntax
udp-helper server ip-address
undo udp-helper server [ ip-address ]
View
VLAN interface view
Parameter
ip-address:
IP address of the destination server.
Description
Use the udp-helper server command to
specify the destination server for UDP broadcast packets.
Use the undo udp-helper server
command to remove the destination server configuration.
No destination server is configured by
default.
At present, you can configure up to 20
destination servers at an interface.
Note: you will remove all the destination
servers under the interface if you carry out the undo udp-helper server command
without an argument.
Related command: display udp-helper
server.
Example
# Configure the device with an IP address
of 192.1.1.2 as the destination server for UDP broadcast packets.
<Sysname> system-view
[Sysname] interface Vlan-interface 1
[Sysname-Vlan-interface1] udp-helper
server 192.1.1.2
