Udp Helper Configuration; Introduction To Udp Helper; Configuring Udp Helper - 3Com S7906E Configuration Manual

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UDP Helper Configuration

When configuring UDP Helper, go to these sections for information you are interested in:

Introduction to UDP Helper

Configuring UDP Helper

Displaying and Maintaining UDP Helper
UDP Helper Configuration Examples
UDP Helper can be currently configured on VLAN interfaces only.
Introduction to UDP Helper
Sometimes, a host needs to forward broadcasts to obtain network configuration information or request
the names of other devices on the network. However, if the server or the device to be requested is
located in another broadcast domain, the host cannot obtain such information through broadcast.
To solve this problem, the device provides the UDP Helper function to relay specified UDP packets. In
other words, UDP Helper functions as a relay agent that converts UDP broadcast packets into unicast
packets and forwards them to a specified destination server.
With UDP Helper enabled, the device decides whether to forward a received UDP broadcast packet
according to the UDP destination port number of the packet.
If the destination port number of the packet matches the one pre-configured on the device, the
device modifies the destination IP address in the IP header, and then sends the packet to the
specified destination server.
If not, the device sends the packet to the upper layer protocol for processing.
Configuring UDP Helper
Follow these steps to configure UDP Helper:
To do...
Enter system view
Enable UDP Helper
Enable the forwarding of
packets with the specified UDP
destination port number(s)
Use the command...
system-view
udp-helper enable
udp-helper port { port-number |
dns | netbios-ds | netbios-ns |
tacacs | tftp | time }
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Remarks
—
Required
Disabled by default.
Required
No UDP port number is
specified by default.