Login
- Table of Contents
-
- H3C S3610[5510] Series Ethernet Switches Operation Manual-Release 0001-(V1.02)
- 00-1Cover
- 00-2Product Overview
- 01-Login Operation
- 02-VLAN Operation
- 03-IP Address and Performance Operation
- 04-QinQ-BPDU Tunnel Operation
- 05-Port Correlation Configuration Operation
- 06-MAC Address Table Management Operation
- 07-MAC-IP-Port Binding Operation
- 08-MSTP Operation
- 09-Routing Overview Operation
- 10-IPv4 Routing Operation
- 11-IPv6 Routing Operation
- 12-IPv6 Configuration Operation
- 13-Multicast Protocol Operation
- 14-802.1x-HABP-MAC Authentication Operation
- 15-AAA-RADIUS-HWTACACS Operation
- 16-ARP Operation
- 17-DHCP Operation
- 18-ACL Operation
- 19-QoS Operation
- 20-Port Mirroring Operation
- 21-Cluster Management Operation
- 22-UDP Helper Operation
- 23-SNMP-RMON Operation
- 24-NTP Operation
- 25-DNS Operation
- 26-File System Management Operation
- 27-Information Center Operation
- 28-System Maintenance and Debugging Operation
- 29-NQA Operation
- 30-VRRP Operation
- 31-SSH Operation
- 32-Appendix
- Related Documents
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| Title | Size | Download |
|---|---|---|
| 22-UDP Helper Operation | 57 KB |
Table of Contents
Chapter 1 UDP Helper Configuration
1.1 Introduction to UDP Helper
1.3 Displaying and Maintaining UDP Helper
1.4 UDP Helper Configuration Example
Chapter 1 UDP Helper Configuration
When configuring UDP Helper, go to these sections for information you are interested in:
l Displaying and Maintaining UDP Helper
l UDP Helper Configuration Example
& Note:
l By default, S3610&S5510 series Ethernet switches do not forward IP broadcast packets. To ensure that UDP Helper is available, you must use the ip forward-broadcast command in system view first. If NTP broadcast mode or DHCP is configured on the switches, the switches will automatically forward broadcast packets. In this case, UDP Helper can take effect even though you do not configure the ip forward-broadcast command. For details about the ip forward-broadcast command, see the “IP Addressing and Performance” part of this manual.
l Currently, UDP Helper configurations relevant with interfaces only apply to VLAN interfaces.
1.1 Introduction to UDP Helper
UDP Helper functions as a relay that converts UDP broadcast packets into unicast packets and forwards them to a specified server.
With UDP Helper enabled, the device decides whether to forward a received UDP broadcast packet according to the port number of the packet. If the packet needs to be forwarded, the device modifies the destination IP address in the IP header and then sends the packet to the specified destination server. Otherwise, the device sends the packet to its upper layer.
With UDP Helper enabled, the device relays broadcast packets of six default UDP ports by default. The default UDP ports are listed in Table 1-1.
Table 1-1 List of default UDP ports
|
Protocol |
UDP port number |
|
TFTP (trivial file transfer protocol) |
69 |
|
DNS (domain name system) |
53 |
|
Time service |
37 |
|
NetBIOS-NS (NetBIOS name service) |
137 |
|
NetBIOS-DS (NetBIOS datagram service) |
138 |
|
TACACS (terminal access controller access control system) |
49 |
1.2 Configuring UDP Helper
Table 1-2 Follow these steps to configure UDP Helper
|
To do… |
Use the command… |
Remarks |
|
Enter system view |
system-view |
— |
|
Enable UDP Helper |
udp-helper enable |
Required Disabled by default |
|
Specify a UDP port |
udp-helper port { port-number | dns | netbios-ds | netbios-ns | tacacs | tftp | time } |
Optional By default, the UDP Helper enabled device converts and forwards broadcast packets of ports 69, 53, 37, 137, 138, and 49. |
|
Enter VLAN interface view |
interface interface-type interface-number |
— |
|
Configure the destination server to which the UDP broadcast packets are to be forwarded |
udp-helper server ip-address |
Required No destination server is configured by default. |
Caution:
l UDP Helper cannot relay DHCP broadcast packets. That is, you cannot set UDP port 67 or 68 (used for DHCP) as the relayed UDP port.
l The dns, netbios-ds, netbios-ns, tacacs, tftp, and time keywords correspond to the six default ports. You can configure the default ports by specifying port numbers or the corresponding parameters. For example, udp-helper port 53 and udp-helper port dns specify the same port.
l When you view the configuration information by using the display current-configuration command, the UDP Helper configuration on default UDP ports is not displayed. The UDP Helper configuration of a default UDP port is displayed only when UDP Helper is disabled on the port.
l The configuration of all UDP ports (including the default ports) is removed if you disabled UDP Helper.
l You can configure up to 256 UDP ports that require relaying and forwarding.
l You can configure up to 20 destination servers at a VLAN interface.
l If the destination server is configured on a VLAN interface, the broadcast packets from a VLAN port to a specific UDP port will be unicast to the destination server configured on that VLAN interface after UDP Helper is enabled.
1.3 Displaying and Maintaining UDP Helper
After performing the above-mentioned configurations, use the display command in any view to display the destination server information and the number of packets forwarded to the corresponding destination server. Verify the configuration result through viewing the running status of the UDP Helper configuration. You can use the reset command in user view to clear statistics about packets forwarded by UDP Helper.
Table 1-3 Follow these steps to display and debug UDP Helper:
|
To do… |
Use the command… |
Remarks |
|
Display the information of the destination server and the number of packets forwarded by UDP relay |
display udp-helper server [ interface interface-type interface-number ] |
Available in any view |
|
Clear statistics about packets forwarded by UDP relay |
reset udp-helper packet |
Available in user view |
1.4 UDP Helper Configuration Example
I. Network requirements
The VLAN interface of a switch has an IP address of 10.110.1.1/16, connecting to network segment 10.110.0.0/16. Specify to forward broadcast packets with destination UDP port 55 to destination server 202.38.1.2/24.
II. Network diagram
Figure 1-1 Network diagram for UDP Helper configuration
III. Configuration procedure
& Note:
The following configuration assumes that the route between the device and the network segment 202.38.1.0/24 is reachable.
# Enable UDP Helper.
<Sysname> system-view
[Sysname] udp-helper enable
# Specify to forward the broadcast packets with destination UDP port being 55.
[Sysname] udp-helper port 55
# Specify the server with the IP address of 202.38.1.2 as the destination server to which UDP broadcast packets are to be forwarded.
[Sysname] interface Vlan-interface 1
[Sysname-Vlan-interface1] ip address 10.110.1.1 16
[Sysname-Vlan-interface1] udp-helper server 202.38.1.2
