Technical Interview Questions

Question 1. what is the difference between URL, URN and URI
Answer:
An Uniform Resource Locator (URL) is the term used to identify an Internet resource, and can be specified in a single line of text.
An Uniform Resource Name (URN) is the term used to identify an Internet resource, without the use of a scheme, and can be specified in a single line of text.
An Uniform Resource Identifier (URI) is used by a browser to identify a single document, and it too can be specified in a single line of text.
The difference between the three is subtle. An URL refers to a Web page, including the scheme, but without a name location. An URN may also include the location of a code fragment. An URI refers to a Web page including the location of the code fragment, if one exists, and the scheme.
URL http://www.pierobon.org/iis/review1.htm
URN www.pierobon.org/iis/review1.htm#one
URI http://www.pierobon.org/iis/review1.htm.html#one

Because Web servers allow for default documents and do not require a scheme to retrieve a document, the subtle difference between an URL and an URN and an URI is hard to tell. URL is now used as the generic term.

Question 2: Give me some examples of default ports used?
Answer:
HTTP: 80
FTP: 21
Telnet: 23
SMTP: 25
POP3: 110
Time Server: 37

For more details see:
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
http://www.iana.org/assignments/port-numbers
Protocol numbering and IP address services are provided by Internet Assigned Numbers Authority (IANA - http://www.iana.org/)