3com S7906E Manuel De Montage

 

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

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Introduction to UDP Helper 

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UDP Helper can be currently configured on VLAN interfaces only. 

 

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.  

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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. 

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If not, the device sends the packet to the upper layer protocol for processing. 

Follow these steps to configure UDP Helper:  

Enter system view 

system-view 

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Enable UDP Helper 

udp-helper enable 

Required 

Disabled by default. 

Enable the forwarding of 
packets with the specified UDP 
destination port number(s) 

udp-helper port { port-number | 
dns | netbios-ds | netbios-ns | 
tacacs | tftp | time } 

Required 

No UDP port number is 
specified by default.