To Next Page

To Previous Page

Operation Manual – UDP Helper

H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1

UDP Helper Configuration

1-1

Chapter 1 UDP Helper Configuration

1.1 Introduction to UDP Helper

UDP Helper is to relay specified UDP packets. In other words, UDP Helper functions as

a relay that converts UDP broadcast packets into unicast packets and forwards them to

a specified server.

With UDP Helper enabled, the device decides whether to forward a received UDP

broadcast packet according to the UDP port number of the packet. If the packet needs

to be forwarded, the device modifies the destination IP address in the IP header and

then sends the packet to the specified destination server. Otherwise, the device sends

the packet to its upper layer.

 Note:

Relay forwarding of BOOTP/DHCP broadcast packets is implemented by the DHCP

relay module using UDP ports 67 and 68, so these two ports cannot be configured as

UDP-Helper relay port.

Table 1-1 lists the default UDP ports that are commonly used to forward broadcast

packets in UDP Helper function. With UDP Helper enabled, the system unicasts the

broadcast packets of those default UDP ports to a specified destination server. You can

also specify other UDP ports to relay broadcast packets.

Table 1-1 List of default UDP ports

Protocol UDP port number

DNS (Domain Name System) 53

NetBIOS-DS (NetBIOS Datagram Service) 138

NetBIOS-NS (NetBIOS Name Service) 137

TACACS (Terminal Access Controller Access

Control System)

TFTP (Trivial File Transfer Protocol) 69

Time Service 37

H3C S3600 Series User Manual

Other manuals for H3C S3600 Series