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How Emails are sent

25 Dec

Every Mail have to go though that MTA(Mail Transfer Agent) to get to the destination. This MTA do give us lot of services, like,

 

  • Receives e-mail from client or another MTA
  • Forwards to destination MTA
  • May store for a while if destination. MTA is unavailable
  • May scan mail for viruses and spam
  • May handle mailing lists and other features


All mail clients are configured with a local MTA. Simply all clients have a MTA. Client do not know how that mail is sent to the recipient. Client use SMTP(Simple Mail Transfer Protocol)(If you don’t know what is SMTP, it is OK just think it as set of rules which apply on that mail transfer. ) to send mail to the gateway.

Mail gateway looks up the right-hand side of the e-mail address in the DNS

An MX (Mail eXchange) record will redirect email sent to any user’s machine (joe@norbert.dept1.cornell.edu, for example) to a designated mail host. It tells the MDA where to route email.

The MX record uses preference values to specify the routing order–low value = high priority. In the example below, when mail is sent to norbert.dept1.cornell.edu the MDA (see Mail Delivery Agent above) tries to reroute the mail to mailhost.dept1.cornell.edu which has the lowest value, and therefore the highest priority. If that fails, it tries mailhost2.dept1.cornell.edu and finally mailhost3.dept1.cornell.edu.

norbert.dept1.cornell.edu                 86400                 A                                   128.253.180.254

norbert.dept1.cornell.edu                86400                MX                10                mailhost.dept1.cornell.edu

norbert.dept1.cornell.edu                86400                MX                20                mailhost2.dept1.cornell.edu

norbert.dept1.cornell.edu                86400                MX                30                mailhost3.dept1.cornell.edu

Using this IP mail is sent to the destination PC. To make the services reliable there are backup MX servers


Mail Lists?

Mailing list address specifies a special mailbox, called a list manager. List Manager sends copies of message to each address on the list sender does not need to know the list of recipients (like we have Google mail groups)

handle: අත, අතගහනවා, අතගා බලනවා, අතට ගන්නවා, අල්ලුව, කයිපුඩිය, කෛපුඩිය, පාලනය කරනවා, පාවිච්ව කරනවා, මිට, වාසිය, වැල් අත, හසුරුවනවා
 
1 Comment

Posted by on December 25, 2010 in Acadamic

 

Tags: , , , ,

One response to “How Emails are sent

  1. jim

    January 11, 2011 at 11:47 am

    good

     

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