1.1.1 display udp-helper server
Syntax
display udp-helper server [ interface Vlan-interface vlan-id ]
View
Any view
Parameters
vlan-id:
VLAN interface number.
Description
Use the display udp-helper server command
to display the UDP broadcast relay forwarding information. The information includes
the VLAN interface enabled with UDP Helper, IP address of the destination
server, and the number of UDP packets forwarded to the destination server. If a
vlan-id is specified, UDP broadcast relay forwarding information of the
specified VLAN interface is displayed.
Examples
# Display the UDP broadcast relay
forwarding information on VLAN-interface 1.
<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-interface 1 is
192.1.1.2, and no packets have been forwarded to the destination server.
Table 1-1 Description
on the fields of the display udp-helper server command
|
Field
|
Description
|
|
Interface
name
|
Interface
enabled with UDP Helper
|
|
Server address
|
Destination server IP address to which
UDP packets are forwarded
|
|
Packets sent
|
Number of UDP packets forwarded to the
destination server
|
1.1.2 reset udp-helper packet
Syntax
reset udp-helper packet
View
User view
Parameters
None
Description
Use the reset udp-helper packet
command to clear UDP Helper statistics.
Examples
# Clear UDP Helper statistics.
<Sysname> reset udp-helper
packet
Syntax
udp-helper enable
undo udp-helper enable
View
System view
Parameters
None
Description
Use the udp-helper enable command to
enable UDP Helper function. After this function is enabled, the switch converts
broadcasts containing the specified port numbers into unicasts and forwards
them to the destination server.
Use the undo udp-helper enable
command to disable UDP Helper function.
By default, UDP Helper is disabled.
Note that: On an S5600 Series Ethernet
Switch, the reception of directed broadcast packets to a directly connected network
is disabled by default. As a result, UDP Helper is available only when the ip
forward-broadcast command is configured in system view. For details about
the ip forward-broadcast command, refer to the IP Address and
Performance part of this manual.
Examples
# Enable UDP Helper.
<Sysname>
system-view
System View: return to User View with
Ctrl+Z.
[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
Parameters
port-number:
Number of the UDP port with which UDP packets are to be forwarded, in the range
0 to 65535 (except for 67 and 68).
dns: Forwards
Domain Name System (DNS) data packets. The corresponding UDP port number is 53.
netbios-ds: Forwards
NetBIOS data packets. The corresponding UDP port number is 138.
netbios-ns: Forwards
NetBIOS name service data packets. The corresponding UDP port number is 137.
tacacs: Forwards
terminal access controller access control system (TACACS) data packet. The
corresponding UDP port number is 49.
tftp: Forwards
Trivial File Transfer Protocol (TFTP) data packets. The corresponding UDP port
number is 69.
time: Forwards
time service data packets. The corresponding UDP port number is 37.
Description
Use the udp-helper port command to configure
the UDP port with which broadcast packets are to be forwarded.
Use the undo udp-helper port command
to remove the configuration.
By default, the UDP Helper enabled device
forwards broadcast packets with any of the six UDP port numbers 53, 138, 137, 49,
69 and 37.
Note that:
l
You need to enable the UDP Helper function
before specifying any UDP port; otherwise, the system prompts error information.
When the UDP helper function is disabled, all configured UDP ports are
disabled, including the default ports.
l
The relaying of BOOTP/DHCP broadcast packets is
implemented through the DHCP relay agent function using UDP port 67 and 68.
That is, the UDP port number cannot be set to 67 or 68 for UDP Helper.
l
The dns, netbios-ds, netbios-ns,
tacacs, tftp, and time keywords correspond to the six
default ports. You can configure the default ports by specifying port numbers
or the corresponding parameters. For example, udp-helper port 53 and udp-helper
port dns specify the same port.
l
When you view the configuration information by
using the display current-configuration command, information about default
UDP ports is not displayed. Such information is displayed only when a default
port is disabled.
l
Currently, you can configure up to 256 UDP ports
on the device.
Examples
# Enable forwarding of UDP broadcasts with a
destination UDP port number of 100.
<Sysname> system-view
System View: return to User View with
Ctrl+Z.
[Sysname] udp-helper port 100
# Disable
forwarding of UDP broadcasts with a destination UDP port number of 53.
[Sysname] undo udp-helper port 53
Syntax
udp-helper server ip-address
undo udp-helper server [ ip-address ]
View
VLAN interface view
Parameters
ip-address:
IP address of the destination server, in dotted decimal notation.
Description
Use the udp-helper server command to
specify the destination server to which the UDP packets are to be forwarded.
Use the undo udp-helper server command
to remove the specified destination server.
No destination server is specified by
default.
Note that:
l
Executing the undo udp-helper server
command without specifying the ip-address argument removes all the
destination servers configured on the current interface.
l
You can specify up to 20 destination server IP addresses
on a VLAN interface.
Related commands: display udp-helper
server.
Examples
# Specify the destination server at
192.1.1.2 for VLAN-interface 1.
<Sysname> system-view
System View: return to User View with
Ctrl+Z.
[Sysname] interface Vlan-interface 1
[Sysname-Vlan-interface1] udp-helper
server 192.1.1.2
# Remove all the specified destination
servers for VLAN-interface 1.
[Sysname-Vlan-interface1] undo udp-helper
server
