Huawei Quidway S5600 Series Operation Manual page 808

Operation Manual – UDP-Helper
Quidway S5600 Series Ethernet Switches-Release 1510
Chapter 1 UDP-Helper Configuration
1.1 Introduction to UDP-Helper
UDP-Helper is designed to relay specified broadcast UDP packets. It enables a device
to operate as a UDP packet relay. That is, it can convert broadcast UDP packets into
unicast packets and forward them to a specified server.
Normally, all the received broadcast UDP packets are passed to the UDP module. With
the UDP-Helper function enabled, the device checks the destination port numbers of
the received broadcast UDP 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 relay ports.
With UDP-Helper enabled, the device relays the broadcast UDP packets whose
destination ports are one of the six UDP ports list in Table 1-1 by default.
Table 1-1 List of default UDP ports
Domain name system (DNS)
NetBIOS datagram service (NetBIOS-DS)
NetBIOS name service (NetBIOS-NS)
TACACS (terminal access controller access control
system)
Trivial file transfer protocol (TFTP)
Time service
Protocol
Huawei Technologies Proprietary
1-1
Chapter 1
UDP-Helper Configuration
UDP port number
53
138
137
49
69
37