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