Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 593
53-1002269-02
Configuring IP parameters – Layer 3 Switches
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PowerConnect(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.
PowerConnect(config)#interface ethernet 1
PowerConnect(config-if-1)#ip directed-broadcast
Syntax: [no] ip directed-broadcast
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 Layer 3 Switch supports both types of IP source routing:
• Strict source routing – requires the packet to pass through only the listed routers. If the Layer
3 Switch receives a strict source-routed packet but cannot reach the next hop interface
specified by the packet, the Layer 3 Switch discards the packet and sends an ICMP
Source-Route-Failure message to the sender.
NOTE
The Layer 3 Switch allows you to disable sending of the Source-Route-Failure messages. Refer
to “Disabling ICMP messages” on page 594.
• 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 Layer 3 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.
To disable forwarding of IP source-routed packets, enter the following command.
PowerConnect(config)#no ip source-route
Syntax: [no] ip source-route
To re-enable forwarding of source-routed packets, enter the following command.
PowerConnect(config)#ip source-route
Enabling support for zero-based IP subnet broadcasts
By default, the Layer 3 Switch treats IP packets with all ones in the host portion of the address as IP
broadcast packets. For example, the Layer 3 Switch treats IP packets with 209.157.22.255/24 as
the destination IP address as IP broadcast packets and forwards the packets to all IP hosts within
the 209.157.22.x subnet (except the host that sent the broadcast packet to the Layer 3 Switch).
Most IP hosts are configured to receive IP subnet broadcast packets with all ones in the host
portion of the address. However, some older IP hosts instead expect IP subnet broadcast packets
that have all zeros instead of all ones in the host portion of the address. To accommodate this type
of host, you can enable the Layer 3 Switch to treat IP packets with all zeros in the host portion of
the destination IP address as broadcast packets.