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 switch 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 commands such 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.
In a dual stack setup, the system sends both A ( for IPv4 — RFC 1035) and AAAA ( for IPv6 — RFC 3596) record requests to a DNS
server even if you configure only the ip name-server command.
Name server, Domain name, and Domain list are VRF specific. The maximum number of Name servers and Domain lists per VRF is six.
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.
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>
To view the current configuration, use the show running-config resolve command.
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IPv4 Routing