Configuring Udp Helper; Displaying And Maintaining Udp Helper - 3Com MSR 50 Series Configuration Manual

648 C 43: UDP H
HAPTER
Configuring UDP
Helper
Displaying and
Maintaining UDP
Helper
C
ELPER ONFIGURATION
Follow these steps to configure UDP Helper:
To do...
Enter system view
Enable UDP Helper
Enable the forwarding of
packets with a specified UDP
destination port number
Enter interface view
Configure the destination
server to which UDP packets
are to be forwarded
c
CAUTION:
On the devices supporting the directed broadcast suppression function, the
■
receiving of directed broadcasts 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
on page 631.
The UDP Helper enabled device cannot forward DHCP broadcast packets. That
■
is to say, the UDP port number cannot be set to 67 or 68.
The dns, netbios-ds, netbios-ns, tacacs, tftp, and time keywords
■
correspond to the six default UDP port numbers. You can configure these
default UDP port numbers by specifying port numbers or the corresponding
parameters. For example, udp-helper port 53 and udp-helper port dns
specify the same UDP port number.
When you view the configuration information by using the display
■
current-configuration command, the UDP Helper configuration of the
default ports will not be displayed. UDP Helper configuration of these ports will
be displayed only after UDP Helper is disabled.
The configuration of all UDP ports (including the default ports) is removed if
■
you disable UDP Helper.
You can configure up to 256 UDP port numbers to enable the forwarding of
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packets with these UDP port numbers.
You can configure up to 20 destination servers on an interface.
■
To do...
Displays the information of
forwarded UDP packets
Use the command...
system-view
udp-helper enable
udp-helper port
{ port-number | dns |
netbios-ds | netbios-ns |
tacacs | tftp | time }
interface interface-type
interface-number
udp-helper server ip-address Required
"IP Performance Configuration"
Use the command...
display udp-helper server
[ interface interface-type
interface-number ]
Remarks
-
Required
Disabled by default
Optional
By default, the UDP helper
enabled device forwards
broadcast packets with any of
the destination port numbers
69, 53, 37, 137, 138, and 49.
-
By default, no destination
server is configured.
Remarks
Available in any view