POP3 Protocol:
The POP (Post Office Protocol 3) protocol provides a simple, standardized way for users to access mailboxes and download messages to their computers.
When using the POP protocol all your eMail messages will be downloaded from the mail server to your local computer. You can choose to leave copies of your eMails on the server as well. The advantage is that once your messages are downloaded you can cut the internet connection and read your eMail at your leisure without incuring further communication costs.
Doing things counts far better than just learning..
lets try it from our terminal to retrieve mails..
Do the following in your terminal to retrieve your mails
* openssl s_client -connect pop.gmail.com:995
This will open up the coonection
* user <username>
* pass <password>
It will get in to your mail box.
* list
list command will list all your mails and its size..
* retr <msg no>
Will display the particular message from your dropbox
* top <msgno> <no.of.lines>
This will display the particular message with no of lines you mentioned
* dele <msg no>
Will delete the message you mentioned
* quit
Will close the session