The first part of a URL (the text before the colon), tells you what kind of communication protocol is desired. This informs your web browser (or email client or whatever) exactly how to interpret the data it finds at the location. Some of the valid protocols are listed in the table below.

Protocol	Description
file :	Name of a file on a hard disk.  Generally it is not a good idea to embed local file names in web pages. Note that if you specify this on a web site it requests a document from the users had drive, not the web site.  file://d:/temp/text.txt    file: Begin file specification d:/ Local disk name temp Directory name text.txt File name
ftp :	File Transfer Protocol - used to copy whole files. Very efficient.  ftp://ftp1.sunet.se/pub5/pc/games/idgames2/planetquake/hereticii/atlas/scylla-blade.zip    ftp:// Start FTP ftp1.sunet.se Name of server pub5 Directory pub5 pc directory pc games directory games idgames2 directory idgames2 planetquake directory planetquake hereticci directory hereticci atlas directory atlas scylla-blade.zip The file to be downloaded from the ftp server.
http :	Hyper-Text Transfer Protocol - A world wide web document which uses Hypertext Markup Language.  http://www.afterzed.com/lessons/index.html    http:// Starts hypertext marker afterzed.com Name of the server on which document resides. Some servers allow the WWW part to be optional. lessons Directory in which file resides. These can be nested. index.html The actual document. If this part is blank, then the server will search the directory for a default document, usually called "default.htm", "default.html", "index.htm", "index.html", "home.htm" or "home.html". Note that the system administrator can make this anything that he wants.
mailto :	Send an email.  mail:lessons@domain.com    mail: Begin mail emailid Mail user name @domain.com Server name
news :	Read news from a newsgroup.  news:alt.newbie    news: Read from a newsgroup alt.newbie The name of the newsgroup to be read.