Configuring Udp Helper - 3Com 5500-EI PWR Install Manual

Table 1-1 List of default UDP ports
DNS (Domain Name System)
NetBIOS-DS (NetBIOS Datagram Service)
NetBIOS-NS (NetBIOS Name Service)
TACACS (Terminal Access Controller Access Control System)
TFTP (Trivial File Transfer Protocol)
Time Service

Configuring UDP Helper

Follow these steps to configure UDP Helper:
To do...
Enter system view
Enable UDP Helper
Specify a UDP port number
Enable the UDP Helper
TTL-keep function
Enter VLAN interface view
Specify the destination server
to which the UDP packets are
to be forwarded
Protocol
Use the command...
system-view
udp-helper enable
udp-helper port { port-number
| dns | netbios-ds | netbios-ns
| tacacs | tftp | time }
udp-helper ttl-keep enable
interface Vlan-interface
vlan-id
udp-helper server ip-address
1-2
UDP port number
53
138
137
49
69
37
Remarks
—
Required
Disabled by default.
Optional
By default, the device enabled
with UDP Helper forwards the
broadcast packets containing
any of the six port numbers 53,
138, 137, 49, 69 and 37.
Optional
Disabled by default. That is,
UDP Helper does not forward
IP broadcasts with the TTL field
being 1.
—
Required
No destination server is
specified by default.