Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 106)

address belongs. Refer to "Designated VLAN for Telnet management sessions to a Layer 2 Switch"
section in the FastIron Ethernet Switch Security Configuration Guide .
Configuring Domain Name Server (DNS) resolver
The Domain Name Server (DNS) resolver feature lets you use a host name to perform Telnet, ping,
and traceroute commands. You can also define a DNS domain on a BrocadeLayer 2 switch or Layer 3
switch and thereby recognize all hosts within that domain. After you define a domain name, the
BrocadeLayer 2 switch or Layer 3 switch automatically appends the appropriate domain to the host
and forwards it to the domain name server.
For example, if the domain "newyork.com" is defined on a BrocadeLayer 2 switch or Layer 3 switch
and you want to initiate a ping to host "NYC01" on that domain, you need to reference only the host
name in the command instead of the host name and its domain name. For example, you could enter
either of the following commands to initiate the ping.
device# ping nyc01
device# ping nyc01.newyork.com
Defining a DNS entry
You can define up to four DNS servers for each DNS entry. The first entry serves as the primary
default address. If a query to the primary address fails to be resolved after three attempts, the next
gateway address is queried (also up to three times). This process continues for each defined gateway
address until the query is resolved. The order in which the default gateway addresses are polled is the
same as the order in which you enter them.
To define four possible default DNS gateway addresses, enter command such as the following:
device(config)# ip dns server-address 10.157.22.199 10.96.7.15 10.95.7.25 10.98.7.15
Syntax: ip dns server-address ip-addr [ ip-addr ] [ ip-addr ] [ ip-addr ]
In this example, the first IP address in the ip dns server-address command becomes the primary
gateway address and all others are secondary addresses. Because IP address 10.98.7.15 is the last
address listed, it is also the last address consulted to resolve a query.
Using a DNS name to initiate a trace route
Suppose you want to trace the route from a BrocadeLayer 2 switch to a remote server identified as
NYC02 on domain newyork.com. Because the newyork.com domain is already defined on the Layer 2
switch, you need to enter only the host name, NYC02, as noted in the following command.
device# traceroute nyc02
Syntax: traceroute host-ip-addr [ maxttl value ] [ minttl value ] [ numeric ] [ timeout value ] [
source-ip ip-addr ]
The only required parameter is the IP address of the host at the other end of the route.
After you enter the command, a message indicating that the DNS query is in process and the current
gateway address (IP address of the domain name server) being queried appear on the screen.
Type Control-c to abort
Sending DNS Query to 10.157.22.199
Tracing Route to IP node 10.157.22.80
Configuring Domain Name Server (DNS) resolver
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