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67
UDP-H
ELPER
C
ONFIGURATION
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.
n
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 591 by default.
Configuring
UDP-Helper
Table 591
List of default UDP ports
Protocol
UDP port number
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
TACACS (terminal access controller access control system)
49
Table 592
Configure UDP-Helper
Operation Command Description
Enter system view
system-view
-
Enable UDP-Helper
udp-helper enable
Required
UDP-Helper is disabled by
default
Summary of Contents for Switch 7757
Page 32: ...32 CHAPTER 1 CLI OVERVIEW...
Page 70: ...70 CHAPTER 5 LOGGING IN USING MODEM...
Page 76: ...76 CHAPTER 7 LOGGING IN THROUGH NMS...
Page 86: ...86 CHAPTER 9 CONFIGURATION FILE MANAGEMENT...
Page 120: ...120 CHAPTER 13 ISOLATE USER VLAN CONFIGURATION...
Page 126: ...126 CHAPTER 14 SUPER VLAN...
Page 136: ...136 CHAPTER 16 IP PERFORMANCE CONFIGURATION...
Page 152: ...152 CHAPTER 17 IPX CONFIGURATION...
Page 164: ...164 CHAPTER 19 QINQ CONFIGURATION...
Page 172: ...172 CHAPTER 21 SHARED VLAN CONFIGURATION...
Page 182: ...182 CHAPTER 22 PORT BASIC CONFIGURATION...
Page 198: ...198 CHAPTER 24 PORT ISOLATION CONFIGURATION...
Page 208: ...208 CHAPTER 25 PORT SECURITY CONFIGURATION...
Page 224: ...224 CHAPTER 27 DLDP CONFIGURATION...
Page 232: ...232 CHAPTER 28 MAC ADDRESS TABLE MANAGEMENT...
Page 240: ...240 CHAPTER 29 CENTRALIZED MAC ADDRESS AUTHENTICATION CONFIGURATION...
Page 280: ...280 CHAPTER 30 MSTP CONFIGURATION...
Page 348: ...348 CHAPTER 35 IS IS CONFIGURATION...
Page 408: ...408 CHAPTER 39 802 1X CONFIGURATION...
Page 412: ...412 CHAPTER 40 HABP CONFIGURATION...
Page 422: ...422 CHAPTER 41 MULTICAST OVERVIEW...
Page 426: ...426 CHAPTER 42 GMRP CONFIGURATION...
Page 480: ...480 CHAPTER 47 PIM CONFIGURATION...
Page 506: ...506 CHAPTER 48 MSDP CONFIGURATION...
Page 552: ...552 CHAPTER 51 TRAFFIC ACCOUNTING CONFIGURATION...
Page 570: ...570 CHAPTER 53 HA CONFIGURATION...
Page 582: ...582 CHAPTER 54 ARP CONFIGURATION SwitchA arp protective down recover interval 200...
Page 622: ...622 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION...
Page 684: ...684 CHAPTER 61 QOS CONFIGURATION...
Page 718: ...718 CHAPTER 63 CLUSTER...
Page 738: ...738 CHAPTER 67 UDP HELPER CONFIGURATION...
Page 752: ...752 CHAPTER 69 RMON CONFIGURATION...
Page 772: ...772 CHAPTER 70 NTP CONFIGURATION...
Page 796: ...796 CHAPTER 72 FILE SYSTEM MANAGEMENT...
Page 802: ...802 CHAPTER 73 BIMS CONFIGURATION...
Page 814: ...814 CHAPTER 74 FTP AND TFTP CONFIGURATION...
Page 830: ...830 CHAPTER 75 INFORMATION CENTER...
Page 836: ...836 CHAPTER 76 DNS CONFIGURATION...
Page 852: ...852 CHAPTER 77 BOOTROM AND HOST SOFTWARE LOADING...
Page 858: ...858 CHAPTER 78 BASIC SYSTEM CONFIGURATION DEBUGGING...