Table of Contents

1 UDP Helper Configuration Guide· 1-1

UDP Helper Configuration Guide· 1-1

Network Diagram·· 1-1

Networking and Configuration Requirements· 1-1

Applicable Product Matrix· 1-1

Configuration Procedure· 1-1

Complete Configuration· 1-2

Precautions· 1-2

 

1  UDP Helper Configuration Guide

UDP Helper Configuration Guide

Ethernet switches provide 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.

l          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.

l          Otherwise, the device sends the packet to the upper layer protocol for processing.

Network Diagram

Figure 1-1 Network diagram for UDP Helper

 

Networking and Configuration Requirements

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).

Applicable Product Matrix

Product series	Software version	Hardware version
S5600 series Ethernet switches	Release 1510, Release 1602	All versions
S3600-SI/EI series Ethernet switches	Release 1510, Release 1602	All versions

 

Configuration Procedure

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

<SwitchA> system-view

[SwitchA] ip forward-broadcast

# Enable UDP Helper on Switch A.

[SwitchA] udp-helper enable

# Configure the switch to forward broadcasts containing the destination UDP port number 137. (By default, the device, after enabled with UDP Helper, forwards the broadcasts containing the destination UDP port number 137.)

[SwitchA] udp-helper port 137

# Specify the destination server on VLAN-interface 1.

[SwitchA] interface Vlan-interface 1

[SwitchA-Vlan-interface1] udp-helper server 192.168.10.2

Complete Configuration

#

 ip forward-broadcast

#

 udp-helper enable

#

interface Vlan-interface

 udp-helper server 192.168.10.2

#

Precautions

l          On an S3600 series , S5600 series Ethernet switch, the reception of directed broadcast packets to a directly connected network is disabled by default, but this feature must be enabled with the ip forward-broadcast command in system view before you can enable UDP Helper. For details about the ip forward-broadcast command, refer to IP Address and Performance Configuration.

l          You need to enable UDP Helper before specifying any UDP port to match UDP broadcasts; otherwise, error information is displayed. When the UDP helper function is disabled, all the specified UDP ports are disabled, including the default ports.