Chapter 1 Udp-Helper Configuration; Introduction To Udp-Helper - H3C S7500 Series Operation Manual

Operation Manual – UDP-Helper
H3C S7500 Series Ethernet Switches

Chapter 1 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 Configuration
UDP-Helper Configuration Example
1.1 Introduction to UDP-Helper
UDP-Helper is designed to relay specified UDP broadcast packets. It enables a device
to operate as a UDP packet relay. That is, it can convert UDP broadcast packets into
unicast packets and forward them to a specified server.
Normally, all the received UDP broadcast packets are passed to the UDP module. With
the UDP-Helper function enabled, the device checks the destination port numbers of
the received UDP broadcast packets and duplicates those with their destination port
numbers being that configured for UDP-Helper to the UDP-Helper module. The
UDP-helper module in turn modifies the destination IP addresses of the packets and
then sends the packet to the specified destination server.
Note:
The DHCP Relay module uses UDP port 67 and 68 to relay BOOTP/DHCP broadcast
packets, so do not use port 67 and 68 as UDP-Helper destination ports.
With UDP-Helper enabled, the device relays the UDP broadcast packets whose
destination ports are one of the six UDP ports list in
Table 1-1 List of default UDP ports
Trivial file transfer protocol (TFTP)
Domain name system (DNS)
Time service
NetBIOS name service (NetBIOS-NS)
Protocol
1-1
Chapter 1 UDP-Helper Configuration
Table 1-1 by default.
UDP port number
69
53
37
137