D-Link DES-3326 User Manual - Domain Name Resolution
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Switch Management and Operating Concepts
93
Domain Name Resolution
The domain name system can be used by contacting the name
servers one at a time, or by asking the domain name system to do
the complete name translation. The client makes a query
containing the name, the type of answer required, and a code
specifying whether the domain name system should do the entire
name translation, or simply return the address of the next DNS
server if the server receiving the query cannot resolve the name.
When a DNS server receives a query, it checks to see if the name is
in its subdomain. If it is, the server translates the name and
appends the answer to the query, and sends it back to the client. If
the DNS server cannot translate the name, it determines what
type of name resolution the client requested. A complete
translation is called recursive resolution and requires the server to
contact other DNS servers until the name is resolved. Iterative
resolution specifies that if the DNS server cannot supply an
answer, it returns the address of the next DNS server the client
should contact.
Each client must be able to contact at least one DNS server, and
each DNS server must be able to contact at least one root server.
The address of the machine that supplies domain name service is
often supplied by a DCHP or BOOTP server, or can be entered
manually and configured into the operating system at startup.
IP Routing
IP handles the task of determining how packets will get from their
source to their destination. This process is referred to as routing.
For IP to work, the local system must be attached to a network. It
is safe to assume that any system on this network can send packets