Email Routing

Every day we send all kinds of emails to clients and internally as an organisation. For local users the process is very simple fire up outlook type in your email and click send.

When the same email sits in the outbox for a few minutes they start losing their minds and hunt for their IT guy to fix the problem.

For today I will not teach you how to fix the outlook problems am sure by now you all know how to handle that.(in case you still have no idea inbox me I will teach you for a few dollars.)We will look in depth on how email is sent and the security challenges it faces. First things first let’s handle the definitions:

Electronic mail (E-mail) is a computer based method of sending messages from one computer user to another.

Computer engineer, Ray Tomlinson invented internet based email in late 1971.

How emails works:

Step 1: mail is created in the Mail User Agent (MUA) and the send button is clicked. This may be done on outlook or any other agent.

Step 2: the mail is routed by the use of MTA/MDA (mail transfer agent/mail delivery agent). The MDA/MTA accepts the e-mail, then routes it to local mailboxes or forwards it if it not locally addressed. An MDA forwards the e-mail to an MTA and it enters the first of a series of "network clouds," labelled as a "Company Network" cloud.

Step 3: this encompasses both public and private cloud with multiple dns mail servers. Depending with your mail service provider your mail will be route accordingly  

Step 4: email queuing. The e-mail addressed to someone at another company enters an e-mail queue with other outgoing e-mail messages. Depending how many mails are send or received will be relative to how long the que will be.

Step 5:  MTA to MTA. When transferring an email, the sending MTA handles all aspects of mail delivery until the message has been either accepted or rejected by the receiving MTA.

Each MTA in the Internet network cloud needs to "wait and ask directions" from the Domain Name System (DNS) in order to identify the next MTA in the delivery chain

Step 6:  virus, spam and firewall filter. As the mail is bounced around it undergoes a series of scans and checks though firewalls. This is what quantifies if a mail should be in your inbox or spam folder.

These are the processes that a mail undergoes from sending to receiving. Usually there are like a million protocols that are available like http, imap, smtp etc.  

When one sends an email address there is ip address attached to it and if you are suspicious you can check out the IP on the mail header. The reasons for doing this is:

•          To detect Spam Emails.

•          To check the authenticity of an email.

•          To track crimes in which email was used as a mode of communication.

Lets use yahoo as an example.

Click on the email message whose headers you want to retrieve. Click on Full Headers at the right most corner of the Email.

 This will open up the mail headers Mail

Lets see gmail:

To obtain Google mail headers

Click on the email message whose headers you want to retrieve.

Click “More Options”/ drop down menu

Click “Show Original”

This will open up the mail headers