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Mohamed G. Gouda					CS 356
Spring 2017						Exercise 3
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What are the six messages that a local DNS server needs to exchange with other
DNS servers in order to resolve the host name (www.x.com) of a web server into
the IP address of this server?

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Solution:
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Msg1	(from local DNS server to root server)
	(IP address of www.x.com server?)

Msg2	(from root server to local DNS server)
	(IP address of www.x.com server?)
	(IP address of com server)

Msg3	(from local DNS server to com server)
	(IP address of www.x.com server?)

Msg4	(from com server to local DNS server)
	(IP address of www.x.com server?)
	(IP address of x.com server)

Msg5	(from local DNS server to x.com server)
	(IP address of www.x.com server?)

Msg6	(from x.com server to local DNS server)
	(IP address of www.x.com server?)
	(IP address of www.x.com server)