Enterasys Networks 9034313-07 manual Configuring Broadcast Settings, Ip directed-broadcast

Models: 9034313-07

1 872
Download 872 pages 24.54 Kb
Page 562
Image 562

Configuring Broadcast Settings

Configuring Broadcast Settings

Purpose

To configure IP broadcast settings. By default, interfaces on the SecureStack C3 do not forward broadcast packets.

Commands

For information about...

Refer to page...

 

 

ip directed-broadcast

19-16

 

 

ip forward-protocol

19-17

 

 

ip helper-address

19-18

 

 

ip directed-broadcast

Use this command to enable or disable IP directed broadcasts on an interface. By default, interfaces on the SecureStack C3 do not forward directed broadcasts. The no form of this command disables IP directed broadcast on the interface.

Syntax

ip directed-broadcast no ip directed-broadcast

Parameters

None.

Defaults

None.

Mode

Interface configuration: C3(su)‐>Router1(Config‐if(Vlan 1))#

Usage

Directed broadcast is an efficient mechanism for communicating with multiple hosts on a network while only transmitting a single datagram. A directed broadcast is a packet sent to all hosts on a specific network or subnet. The directed broadcast address includes the network or subnet fields, with the binary bits of the host portion of the address set to one. For example, for a network with the address 192.168.0.0/16, the directed broadcast address would be 192.168.255.255. For a subnet with the address 192.168.12.0/24, the directed broadcast address would be 192.168.12.255.

In order to minimize broadcast DoS attacks, forwarding of directed broadcasts is disabled by default on the SecureStack C3, as recommended by RFC 2644.

If the ability to send directed broadcasts to a network is required, you should enable directed broadcasts only on the one interface that will be transmitting the datagrams. For example, if a SecureStack C3 has five routed interfaces for the 10, 20, 30, 40, and 50 networks, enabling directed

19-16 IP Configuration

Page 562
Image 562
Enterasys Networks 9034313-07 manual Configuring Broadcast Settings, Ip directed-broadcast