Udp Helper; Overview Of Udp Helper - 3Com 4200G 12-Port Configuration Manual

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Overview of UDP
Helper

UDP Helper

Configuration
Enabling/disabling UDP
Helper Function
Configuring UDP Port
with Replay Function
UDP H
ELPER
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 include:
Enabling/disabling UDP Helper function
■
Configuring UDP port with replay function
■
Configuring the relay destination server for broadcast packets
■
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.
Table 348 UDP Helper function
Operation
Enable UDP Helper function
Disable UDP Helper function
By default, UDP Helper function is disabled.
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 349 Default UDP ports list
Protocol
Trivial File Transfer Protocol (TFTP)
Domain Name System (DNS)
Time service
NetBIOS Name Service (NetBIOS-NS)
NetBIOS Datagram Service (NetBIOS-DS)
Terminal Access Controller Access Control System
(TACACS)
C
ONFIGURATION
Command
udp-helper enable
undo udp-helper enable
UDP port ID
69
53
37
137
138
49