Reference Guide

Enabling Directed Broadcast
By default, FTOS drops directed broadcast packets destined for an interface. This default setting provides some
protection against denial of service (DoS) attacks.
To enable FTOS to receive directed broadcasts, use the following command.
• Enable directed broadcast.
INTERFACE mode
ip directed-broadcast
To view the configuration, use the show config command in INTERFACE mode.
Resolution of Host Names
Domain name service (DNS) maps host names to IP addresses. This feature simplifies such commands as Telnet and
FTP by allowing you to enter a name instead of an IP address.
Dynamic resolution of host names is disabled by default. Unless you enable the feature, the system resolves only host
names entered into the host table with the ip host command.
The following sections describe DNS and the resolution of host names.
• Enabling Dynamic Resolution of Host Names
• Specifying the Local System Domain and a List of Domains
• Configuring DNS with Traceroute
Enabling Dynamic Resolution of Host Names
By default, dynamic resolution of host names (DNS) is disabled.
To enable DNS, use the following commands.
• Enable dynamic resolution of host names.
CONFIGURATION mode
ip domain-lookup
• Specify up to six name servers.
CONFIGURATION mode
ip name-server ip-address [ip-address2 ... ip-address6]
The order you entered the servers determines the order of their use.
To view current bindings, use the show hosts command.
Example of the show hosts Command
FTOS>show host
Default domain is force10networks.com
Name/address lookup uses domain service
Name servers are not set
Host Flags TTL Type Address
-------- ----- ---- ---- -------
ks (perm, OK) - IP 2.2.2.2
patch1 (perm, OK) - IP 192.68.69.2
tomm-3 (perm, OK) - IP 192.68.99.2
gxr (perm, OK) - IP 192.71.18.2
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