2.6 DNS Records

1.	Suppose that a web browser user is requesting the page www.somesite.com/index.html. For the user’s host to be able to send an HTTP request message to the web server www.somesite.com, the user’s host is required to determine its IP address. This is done as follows:
2.	Suppose that a web browser user is requesting the page www.somesite.com/index.html. For the user’s host to be able to send an HTTP request message to the web server www.somesite.com, the user’s host is required to determine its IP address. This is done as follows:
3.	Suppose that a web browser user is requesting the page www.somesite.com/index.html. For the user’s host to be able to send an HTTP request message to the web server www.somesite.com, the user’s host is required to determine its IP address. This is done as follows:

	a)	In a Type A, i.e. Type = A, then Name is a hostname and Value is the IP address for the host, e.g. (machineX.departmentY.companyZ.com, 122.94.21.126, A).
	b)	In a Type NS, i.e. Type = NS, then Name is a domain and Value is the hostname of the authoritative DNS server that knows how to obtain IP addresses for hosts on the domain, e.g. (companyZ.com, dns.companyZ.com, NS).
	c)	In a Type CNAME, i.e. Type = CNAME, then Value is a canonical name for the alias hostname Name, e.g. (companyZ.com, machineX.departmentY.companyZ.com, CNAME).
	d)	In a Type MX, i.e. Type = MX, then Value is a canonical name of a mail server that has an alias hostname Name, e.g. (companyZ.com, mail.departmentY.companyZ.com, MX).

2.6 DNS Records

4.	Note that host aliasing is used for a host with a complicated hostname.
5.	Then, a simpler alias name can be associated with it. The DNS provide host name-alias name mapping as described above.