How Does an Email Address Lookup Work?
Other People Are Reading
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Names and Numbers
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A server (host) on the Internet is ultimately found by its Internet Protocol (IP) address--a number like 72.14.205.147. In the mid-1980's, Internet engineers developed the Domain Name System (DNS) to map more friendly names to these numbers. When your email server attempts to deliver a message to someone at hotmail.com, for instance, it uses DNS to find the IP address for email at hotmail.com.
Different DNS Entries
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The Domain Name System is capable of managing several different records for the same domain name. The mail exchange (MX) record lists what machine is receiving mail for the domain. A name server (NS) record lists which machine responds to DNS requests for the domain. Address (A) records are used to map friendly names to IP addresses within the domain.
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Email Address Decomposition
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In an email address such as webmaster@hotmail.com, the portion to the right of the "@" symbol is a domain name. The portion to the left represents a unique mail account in that domain. This email address could be read as the Webmaster account in the hotmail portion of the commercial domain.
Putting It All Together
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To actually forward email to webmaster@hotmail.com, your own email server will check DNS for the mail exchange (MX) record listed for hotmail.com. The first query returns the hostname receiving mail for hotmail.com. Your mail server will use the IP address it gets from the address record to open a session and send your mail.
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Resources
- Photo Credit All graphics created by Paul Nelis
