Alcatel Carrier Internetworking Solutions 6648 - Manual (Page 117)

OmniSwitch Troubleshooting Guide September 2005 page 6-1
6 Troubleshooting DNS
In order to troubleshoot a DNS problem, a basic understanding of the protocol/feature is required. Some
basic concepts are covered below. Reading the “Enabling the DNS Resolver” section in the “Logging Into
the Switch” chapter in the appropriate OmniSwitch Switch Management Guide is highly recommended.
In This Chapter
“Introduction” on page 6-1
“Troubleshooting a DNS Failure” on page 6-2
“DNS Configuration Considerations” on page 6-3
Introduction
The primary function of Domain Name Service or DNS enables the user to enter a pre-configured name
rather than an IP address to reach another host, via telnet, ftp, or ping. Once requested the switch contacts
a DNS server to find out what IP address is mapped to the name. If the server finds the entry a response is
sent to the switch indicating what IP address the name is associated with. The switch then attempts to
execute the command to the IP address. You can set up to 3 DNS servers from the CLI, WebView, or
through SNMP. If one server does not know the resolution the next server is queried to see if it knows the
resolution. You can also configure a domain name that the switch can belong to.
For example, say you want to set the domain name to “Alcatel.com” rather than entering
-> ping switch1.Alcatel.com
you could just enter
-> ping switch1
For all other domains you still need to enter the full syntax (ping switch2.xylan.com).