DNS

The Domain Name System (DNS) resolves host names (e.g. jmvidal.cse.sc.edu) into their corresponding IP numbers (129.252.11.88). It is described in a series of RFCs.
IP numbers relate to the physical layout of the network. They are used for routing.
It is hierarchical. Each domain (sc.edu) has its own authority. If it does not know the mapping it will ask a higher domain (.edu) ending in one of the eight root DNS servers. For example:
- When your machine hadar.cse.sc.edu needs to know the IP for www.wastingtime.com it will ask your local DNS server (cse). If it does not have it cached, it will ask the next one higher up (sc).
Domain names relate to ownership and responsibility. They are meant to be used by humans.

In Unix the whois command can be used to get ownership information: whois sc.edu

Registrant:
University of South Carolina (SC6-DOM)
   1244 Blossom Street
   Columbia, SC 29208
   US

   Domain Name: SC.EDU

   Administrative Contact:
      Yarbrough, Stan  (SY1779)  syarb@GWM.SC.EDU
      University of South Carolina
      1244 Blossom Street
      Columbia, SC 29208
      803-777-7474 (FAX) 803-777-1900
   Technical Contact:
      Mowery, Bill  (BM13149)  bill.mowery@SC.EDU
      University of South Carolina
      514 Main Street
      Columbia, SC 29208
      803-777-4636 (FAX) 803-777-8644
   Billing Contact:
      Wider, Ella  (EW1183)  wider-ella@SC.EDU
      USC DLIS
      Thomas Cooper Library
      Columbia, SC 29208
      (803) 777-2498

   Record last updated on 14-Dec-2001.
   Record created on 07-Mar-1995.
   Database last updated on 26-Dec-2001 23:14:00 EST.

   Domain servers in listed order:

   THEUSC.CSD.SC.EDU		129.252.41.11
   SPARKY.CSD.SC.EDU		129.252.42.25