3Com Switch 8800 Family Configuration Guide

734 CHAPTER 63: UDP HELPER CONFIGURATION
Table 675 shows the list of default UDP ports.
Specify the UDP ports whose
packets need to be forwrded
udp-helper port { port | dns |
netbios-ds | netbios-ns |
tacacs | tftp | time }
Optional
1 When the function is
enabled, the broadcast
packets of the default UDP
ports are unicast to the
corresponding destination
server. Refer to
Table 675
for the list of default UDP
ports.
2 The system supports up to
256 UDP ports.
3 The UDP port number is in
the range of 1 to 65,535.
UDP broadcast packets of
port 0, port 67, and port
68 cannot be forwarded.
Enter VLAN interface view
Interface Vlan-interface
interface -number
-
Configure the destination
server to which the UDP
packets are forwarded
udp-helper server ip-address
Required
■ Up to 20 destination
servers are corresponding
to a VLAN interface.
■ Suppose a destination
server is configured on a
VLAN interface. When the
function of forwarding
UDP broadcast packets is
enabled, all the broadcast
packets received on the
VLAN interface from the
specified UDP ports are
unicast to the destination
server corresponding to
the VLAN interface.
■ By default, the destination
server to which the UDP
packets are forwarded is
not configured.
Tabl e 675 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 server (NetBIOS-NS) 137
NetBIOS datagram server (NetBIOS-DS) 138
Terminal access controller access control system (TACACS) 49
Table 674 Configure UDP helper
Operation Command Description