Administrator Guide
Enabling Directed Broadcast
By default, the system drops directed broadcast packets destined for an interface. This default setting provides some protection
against denial of service (DoS) attacks.
To enable the system to receive directed broadcasts, use the following command.
• Enable directed broadcast.
INTERFACE mode
ip directed-broadcast
To view the conguration, use the show config command in INTERFACE mode.
Resolution of Host Names
Domain name service (DNS) maps host names to IP addresses. This feature simplies 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
• Conguring 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.
Example of the show hosts Command
To view current bindings, use the show hosts command.
Dell>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
f00-3 (perm, OK) - IP 192.71.23.1
Dell>
IPv4 Routing
385