DNS provides for domain name to IP address resolution. Host names are not case sensitive and can contain alphabetic or numeric letters or the hyphen. Avoid the underscore. A fully qualified domain name (FQDN) consists of the host name plus domain name as in the following example:
Top level domains are .com, .edu, .net, .org, and more. Second level domains may contain other domains and hosts.
- CACHE.DNS - The DNS Cache file. This file is used to resolve internet DNS queries. It is located in the WINNTROOT\system32\DNS directory and is used to configure a DNS server to use a DNS server on the internet to resolve names not in the local domain.
DNS and WINS
For the system to use WINS if DNS resolution cannot supply the IP address for a name, all DNS servers must be configured to use WINS. It cannot be done with just the primary DNS server.
Types of DNS Servers
Three types of name servers:
- Primary - Locally stored files exist on the name server data base.
- Secondary - Gets data called a zone transfer from another server that is the zone authority.
- Caching - Only caches name server information and does not contain its own files.
The caching only name server generates no zone transfer traffic. A DNS Server that can communicate outside of the private network to resolve a DNS name query is referred to as forwarder.
- Recursive - When performed for a client, the DNS server stays with the query until it is resolved. The answer is returned or an error is returned.
- Iterative - The server when it does not have the answer will refer the client to another name server that may have the answer. The best answer the name server has is returned even if it is partial. Usually used between name servers to obtain partial name resolutions.
- Reverse - The client provides the IP address and asks for the name. In other queries the name is provided, and the IP address is returned to the client. Reverse lookup entries for a network 192.168.100.0 is "100.168.192.in-addr arpa".