Configuring IP

NOTE: A less common type, the all-sub-nets broadcast, goes to all directly-attached sub-nets. Forwarding for this broadcast type also is supported, but most networks use IP multicasting instead of all-sub-net broadcasting.

Forwarding for all types of IP directed broadcasts is disabled by default. You can enable forwarding for all types if needed. You cannot enable forwarding for specific broadcast types.

To enable forwarding of IP directed broadcasts, use either of the following methods.

USING THE CLI

HP9300(config)# ip directed-broadcast

Syntax: [no] ip directed-broadcast

HP software makes the forwarding decision based on the routing switch’s knowledge of the destination network prefix. Routers cannot determine that a message is unicast or directed broadcast apart from the destination network prefix. The decision to forward or not forward the message is by definition only possible in the last hop router.

To disable the directed broadcasts, enter the following command in the CONFIG mode:

HP9300(config)# no ip directed-broadcast

To enable directed broadcasts on an individual interface instead of globally for all interfaces, enter commands such as the following:

HP9300(config)# interface ethernet 1/1

HP9300(config-if-1/1)# ip directed-broadcast

Syntax: [no] ip directed-broadcast

USING THE WEB MANAGEMENT INTERFACE

1.Log on to the device using a valid user name and password for read-write access. The System configuration panel is displayed.

2.Click on the plus sign next to Configure in the tree view to display the list of configuration options.

3.Click on the plus sign next to IP to display the list of IP configuration options.

4.Select the General link to display the IP configuration panel.

5.Select Enable or Disable next to Directed Broadcast Forward.

6.Click the Apply button to save the change to the device’s running-config file.

7.Select the Save link at the bottom of the dialog. Select Yes when prompted to save the configuration change to the startup-config file on the device’s flash memory.

Disabling Forwarding of IP Source-Routed Packets

A source-routed packet specifies the exact router path for the packet. The packet specifies the path by listing the IP addresses of the router interfaces through which the packet must pass on its way to the destination. The routing switch supports both types of IP source routing:

•Strict source routing – requires the packet to pass through only the listed routers. If the routing switch receives a strict source-routed packet but cannot reach the next hop interface specified by the packet, the routing switch discards the packet and sends an ICMP Source-Route-Failure message to the sender.

NOTE: The routing switch allows you to disable sending of the Source-Route-Failure messages. See “Disabling ICMP Messages” on page 6-34.

•Loose source routing – requires that the packet pass through all of the listed routers but also allows the packet to travel through other routers, which are not listed in the packet.

The routing switch forwards both types of source-routed packets by default. To disable the feature, use either of the following methods. You cannot enable or disable strict or loose source routing separately.

6 - 33