When Roy Tomlinson sent the first email, he might not be knowing that his act is going to change the very face of communication. Email is one of the most used modes of communication. The sender is free to write a message body comprising of one sentence to almost the whole of the book (if time allows) in an email, without thinking of the charges. Actually, there are no charges involved. With an internet connection at home and a device connected to the network, you are not paying even for the ride to the cybercafé. The process may look quite simple and fast, but it is certainly not the same at the backend. Lets’ take a look at the technical terms and the steps involved in sending of email from the sender to the recipient.
@ – a story behind how is the email sent
Roy Tomlinson, the father of email or electronic mail, used a sign of @ to define the starting point and ending point of an email. He generated the first email address using this character from the keyboard. The email address looks something like email@example.com. Thus, @ sign displayed the domain between which send and receive function is performed. Earlier, computers were machines that came with dial-up terminals. The machines had a record of all the users. With the passage of time, these machines that held the record of the users got the name ‘server’. The email is just a text message. It is sent from one machine to another, unlike an SMS text which is designed for mobile phone environments.
Working entities behind the movement of email
How a machine is identified as a sender and the other as a receiver? What is actually happening when someone sends an email? Let’s try to understand.
When we write an email message and direct it to the recipient’s email address, certain servers come into the picture. The first server is SMTP or simple mail transfer protocol. The SMTP acts as an outgoing mail server. Its job is to identify the address and the corresponding machine and start the sending process. SMTP finds it tricky to understand domains, it is where the email ID is located. So, it connects with the DNS or domain name system server.
The DNS is just like a phone directory but has the I.P addresses instead of street numbers and phone numbers. The DNS converts the domain name into the I.P. address. It performs one more important task. This task is finding if the target domain has a mail exchange server or not. The mail exchange server is analogous to a letter recipient’s mailbox. When the exchange server is found out, the mail resides there. This server receiving mail is called Mail Transfer Agent or Message Transfer Agent.
Now, let’s find out what happens at the recipient’s end. The mail server that enables receiving of the email is actually called POP or IMAP.
POP stands for Post Office Protocol. It is actually collecting the incoming mail just like a post office of the area that collects all letters directed to it. So, it is the POP where the recipient actually finds the incoming mail. It simply grabs all the emails and does leave a copy of it one server too. This, therefore, can lead to eating up of the resource or server space. POP, however, is useful as it can grab all the emails coming from various types of servers, and consolidate them in one mailbox.
This mailbox is the one that you use, like Gmail. The only disadvantage of POP is that it is not of much use in present times when the recipients are receiving mails from various kinds of interfaces instead of only one. The receiver can find the task of sorting mails filled with chaos and confusion. So, the answer to this situation lies in IMAP, a smarter protocol expanded as Internet Message Access Protocol.
IMAP is the smarter protocol as it is bi-directional in function, unlike POP which is unidirectional. IMAP is that assistant of yours that categorizes the mails for you and delivers them to you at the device of your choice. The emails are read while on being a mobile network, while on the move, or using home or office internet connection when the clients are at some premise having connectivity.
The treatment of mail messages, accordingly, has to change. IMAP interacts back with the server where incoming mail is stored. So, when the email is read over a mobile device, it is marked as read. Thus, the effort in finding new mails is reduced.
The other feature of IMAP is that it works offline too. The recipient will get to see only the synced email box comprising of reading and unread messages as the IMAP does the synchronizing part for the recipient. IMAP, thus, is more relevant and is designed to park the mails in POP, too, to enable the recipient to consolidate those when required.
How to email servers identify the erroneous mails marked by the sender to sender
Any server can be made to act like a recipient server. There is no discrimination made in the working of a recipient server. However, the trick lies in selecting the sender server. In the sender server, the arrangements are to made to ensure that the sender does not end up sending emails to the self. It is done by following a simple technique. Firstly, SMTP servers have static IP addresses. Also, the ISP’s server invariably block port 25 in their servers. This port, if left active, can wreak havoc on communication and the sender will land up getting its own bandwidth eaten up due to spam mail.
Errors related to email delivery
Seldom it happens that the screen flashes the message – email sending failed. There are a few reasons responsible for this:
1) Bouncing of email:
It happens if the recipient’s mailbox is full, it also happens when the address of the recipient is non-existent. Mailer Daemon or the Postmaster is the senders who inform the sender about the reason and the time when the sending was attempted.
2) SMTP issues:
If the SMTP selected is not approved by the recipient server, or has quality issues, it can lead to email delivery failure.
3) Malware attack:
A malware can block the emails coming to the mailbox and can spam it with unwanted emails. The malware can also show its presence by sending you a delivery notification for the emails that you did not send.
So, this is how email is sent. It is a common process but knowing the story behind it is surely going to change your perspective next time when you click ‘Send’.