DNS is primarily used for two purposes: Translating names like
www.atc.no to the corresponding IP address (commonly referred to as "resolving a host name", or "forward lookup"), and translating IP addresses to it's assiciated host name (commonly referred to as "resolving an IP address", or "reverse lookup").
Most networks are configured with one or more DNS server which speaks to other DNS servers on the internet. While the domain name structure is a strict hierarchy, there are no rules for what DNS servers may speak to each other. As a matter of fact, most DNS servers will happily answer queries made by any host on the internet.
Problems with DNS lookups is the single most common problem when your web browser is unable to show the web page you are trying to reach. As a rule of thumb, you should always talk to the DNS server closest to you (in terms of network connectivity), this usually means you should ask your internet service provider for their DNS server addresses and use those.
Below is a list of current DNS server addresses you may find useful. PLEASE remember that the addresses may change; this list may not be up to date:
ATC: 195.159.120.10 and 195.159.62.114
NSN: 195.159.62.110 and 195.159.62.111
Telenor: 148.122.208.98 and 148.122.161.2
Powertech: 195.159.0.100 and 195.159.0.200
NextGenTel: 217.13.4.21 and 217.13.7.136
UPC: 193.150.195.21 and 212.186.255.130
