48
UDP H
ELPER
C
ONFIGURATION
Overview of UDP
Helper
The major function of UDP Helper is to relay-forward UDP broadcast packets, that is,
it can convert UDP broadcast packets into unicast packets and send to the designated
server, as a relay.
When UDP Helper starts, the switch can judge if to forward the UDP broadcast
packets received at the port based on UDP port ID. If yes, the switch then modifies the
IP address in the IP packet header and sends the packet to the designated destination
server. Otherwise, it sends the packet to the upper layer module for further
processing.
UDP Helper
Configuration
UDP Helper configuration include:
■
Enabling/disabling UDP Helper function
■
Configuring UDP port with replay function
■
Configuring the relay destination server for broadcast packets
Enabling/disabling UDP
Helper Function
When UDP Helper function is enabled, you can configure the UDP ports where UDP
function is required and the relay function is enabled at UDP ports 69, 53, 37, 137,
138 and 49. When the function is disabled. Relay function configured at all UDP
ports, including the default six ports, shall be disabled.
Perform the following configuration in system view.
By default, UDP Helper function is disabled.
Configuring UDP Port
with Replay Function
When UDP relay function is enabled, the system by default forwards the broadcast
packets on the UDP ports listed in Table 349. You can configure up to 256 UDP ports
with relay function.
Table 348
UDP Helper function
Operation
Command
Enable UDP Helper function
udp-helper enable
Disable UDP Helper function
undo udp-helper enable
Table 349
Default UDP ports list
Protocol
UDP port ID
Trivial File Transfer Protocol (TFTP)
69
Domain Name System (DNS)
53
Time service
37
NetBIOS Name Service (NetBIOS-NS)
137
NetBIOS Datagram Service (NetBIOS-DS)
138
Terminal Access Controller Access Control System
(TACACS)
49
Summary of Contents for 4200G 12-Port
Page 10: ...8 CONTENTS...
Page 14: ...4 ABOUT THIS GUIDE...
Page 46: ...32 CHAPTER 5 LOGGING IN THROUGH WEB BASED NETWORK MANAGEMENT SYSTEM...
Page 48: ...34 CHAPTER 6 LOGGING IN THROUGH NMS...
Page 60: ...46 CHAPTER 9 VLAN CONFIGURATION...
Page 64: ...50 CHAPTER 10 MANAGEMENT VLAN CONFIGURATION...
Page 80: ...66 CHAPTER 13 GVRP CONFIGURATION...
Page 98: ...84 CHAPTER 15 LINK AGGREGATION CONFIGURATION...
Page 112: ...98 CHAPTER 18 MAC ADDRESS TABLE MANAGEMENT...
Page 126: ...112 CHAPTER 19 LOGGING IN THROUGH TELNET...
Page 162: ...148 CHAPTER 20 MSTP CONFIGURATION...
Page 274: ...260 CHAPTER 29 IGMP SNOOPING CONFIGURATION...
Page 276: ...262 CHAPTER 30 ROUTING PORT JOIN TO MULTICAST GROUP CONFIGURATION...
Page 298: ...284 CHAPTER 33 SNMP CONFIGURATION...
Page 304: ...290 CHAPTER 34 RMON CONFIGURATION...
Page 338: ...324 CHAPTER 36 SSH TERMINAL SERVICES...
Page 356: ...342 CHAPTER 38 FTP AND TFTP CONFIGURATION...
Page 365: ...Information Center Configuration Example 351 S4200G terminal logging...
Page 366: ...352 CHAPTER 39 INFORMATION CENTER...
Page 378: ...364 CHAPTER 40 BOOTROM AND HOST SOFTWARE LOADING...
Page 384: ...370 CHAPTER 41 Basic System Configuration and Debugging...
Page 388: ...374 CHAPTER 43 NETWORK CONNECTIVITY TEST...
Page 406: ...392 CHAPTER 45 CONFIGURATION OF NEWLY ADDED CLUSTER FUNCTIONS...