Avaya 580 Manual Do Utilizador

Document No. 10-300077, Issue 2

11-3

Configuring DNS Client

Typically, a network will have a local DNS server which provides 
translations for devices in the local network. That server will also “know” 
the IP address of the Root servers. When a client attempts to communicate 
with a device by its name, the IP portion of the protocol stack will recognize 
that a name (not an address) has been specified. It will then contact the local 
DNS server and request the name be translated into an IP address. For 
example: if a user types 

 

, 

that name will be sent 

to the local DNS server. If the DNS server has that information, it will 
respond with the appropriate IP address.

If the DNS server does not have that address translation, it will contact the 
root server using the IP address for that root server. In this example, it 
would use the IP address for the .COM root server.

Root servers do not have specific translations for names, but they do have 
the database of master name servers. The root server would the avaya.com 
master name server using the avaya.com IP address.

The root server would then send a request to the master name server 
requesting the translation. In small subdomains, a single DNS server may be 
adequate for servicing the subdomain and be able to translate all DNS 
requests. So the master name server may act as the individual name server 
by providing the translations. 

In large subdomains, a single DNS server may be inadequate to handle all 
of the address translations. In these cases, the master name server may point 
to other individual name servers. In this case, we are pinging the Web server 
www.avaya.com. Assume for this example that Avaya has a single DNS 
server for the entire subdomain of avaya.com. The avaya.com DNS server 
would use the IP address of the Avaya Web server.

The client would then insert the IP address into the IP packets going to the 
destination. In this example, it would put the IP address in the HTTP packet 
going to the Avaya Web site.

The benefit of using DNS is that you need only know the name of the server 
instead of the IP address for which you are trying to communicate. Also, if 
the IP address of the server changes, you need only update the DNS 
database.

Many vendors provide DNS servers. Consult the DNS Server vendor’s 
documentation for information on configuring the DNS server. Virtually 
every IP protocol stack includes DNS client capabilities. The Avaya 
multiservice switch is a DNS client only.