3com 4200G ユーザーズマニュアル

The Switch 5500 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 a pre-configured port 
number 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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Otherwise, the device sends the packet to the upper layer protocol for 
processing.

Figure 79   Network diagram for UDP Helper

 

PC A resides on network segment 192.168.1.0/24 and PC B on 192.168.10.0/24; 
they are connected through Switch A and are reachable to each other.

It is required to configure UDP Helper on the switch, so that PC A can find PC B 
through computer search (Computer search uses broadcasts with the destination 
UDP port 137).

# Enable Switch A to receive directed broadcasts to a directly connected network.

[SwitchA] ip forward-broadcast 

# Enable UDP Helper on Switch A.

Vlan-int1

192.168.1.1/24

Switch A

PC A

192.168.1.2/24

Vlan-int2
192.168.10.1/24

PC B

192.168.10.2/24

Switch 5500

Release V03.02.04 

All versions

Switch 5500G

Release V03.02.04 

All versions

Switch 4500

Release V03.03.00 

All versions