The Difference Between POP3 and IMAP

There are two different protocols available to access e-mail: POP3 and IMAP. POP3 is useful when e-mail is checked from only one computer. IMAP is the better choice when you would like to check your mail from multiple computers, at work and home, for example. IMAP has the added benefit of accessing folders on the server, allowing you to organize your e-mail, and access it from anywhere. If you use Webmail, you should use IMAP on all of your e-mail clients. Use of a POP3 mail client in association with Webmail can cause errors in your inbox that will result in a temporary loss of access to your mail.

The Difference

POP3 works by reviewing the inbox on the mail server, and downloading the new messages to your computer. Clients can access their inboxes. no other folders on the server can be accessed. POP3 only handles retrieval of messages from a client's inbox. When using POP3, your mail is stored on your PC.

IMAP downloads the headers of the new messages on the server, then retrieves the message you want to read when you click on it. IMAP4 can be used to access multiple mailboxes and mailbox folders, and public folders, as well. When using IMAP, the mail is stored on the mail server. Unless you copy a message to a "Local Folder" the messages are never copied to your PC.

Webmail (a.k.a. Outlook Web Access) uses HTTP/HTTPS to provide Web browser-based access to clients' inboxes, their other mail folders and to public folders.

Scenarios of Use

POP3

• You only check e-mail from one computer.

• You want to remove your e-mail from the mail server.

IMAP

• You check e-mail from multiple locations. at work and home

• You use Webmail.

Tips Keep your Inbox small! This will speed up your e-mail retrieval. Checking the e-mail is directly dependent on how many e-mail messages are in your inbox on the mail server.

POP3

• Set to remove mail from server after 30 days.

• Don't check more frequently than every 15 minutes.

• 75 MB is the maximum for POP3 users. POP'ing large mail boxes consumes excessive server resources.

IMAP

Do NOT check all folders for new messages! This slows your e-mail substantially.

• Use "mail/" ( without the quotes ) as your IMAP folder directory.

• You can set your client to download the mail and to remove the mail from the server, like a POP3 client.

• Organize your mail into folders, and archive your older messages. This speeds e-mail retrieval by minimizing the number of messages in the inbox.

POP3	IMAP
Downloads messages to computer and deletes from server.	Downloads only header of the message. It retrieves the message only if you want to read.
Only inbox is accessible. No other folder on the server can be accessed.	Cab be used to access multiple mail box and mail box folders.
Mail is stored in PC	Mail is stored in server, unless you copy the message to local folder.
Choose if You only check e-mail from one computer	Choose if You check e-mail from multiple locations. at work and home
Choose if You want to remove your e-mail from the mail server	Choose if You use Webmail.