Home
Comparing IMAP and POP
This document was developed to help you make an informed decision on which protocol is best for you. Recommendations
  • If you check mail from multiple machines-- Use IMAP.
  • If you travel -- Use IMAP.
  • If you are happy with your current settings -- Use POP.
POP Post Office Protocol (POP) is the most commonly used internet mail protocol. The POP protocol is the easiest to implement and use. Until recently mail servers and client readers only supported POP. POP is still the default protocol for most mail reader clients. POP's Positive Features
  • Clients are available for PCs, Macs, and Unix.
  • Clients for Windows 95/98/NT include Eudora 5.x, Microsoft Outlook and Express, and Netscape 5.x.
  • All of the messages are and all of the mailbox information is kept on the local machine.
POP's Limitations
  • POP assumes that the user has only one client (computer).
  • All messages are downloaded regardless of size.
  • All messages are stored on the client machine. Therefore you do not have access to the mail boxes if you are away from your client machine.
  • Slower than IMAP -- Mailbox information is copied each time you check your mail.
IMAP Internet Message Access Protocol (IMAP) was created at Stanford University in 1986. IMAP is based on a client server model where all the mailbox and messages are maintained on the server. IMAP allows the client to access remote messages as if they were stored locally. The client issues commands to download them or delete them, access and set message state information, but the server always maintains the information. IMAP allows for faster service because the client reads all of the message headers without having to download all of the actual messages. IMAP's Positive Features
  • Clients are available for PCs, Macs, and Unix.
  • Clients for Windows 95/98/NT include Eudora 5.x, Microsoft Outlook Express, and Netscape 5.x.
  • All of the messages are and all of the mailbox information is kept on the server, so it can always be accessed. All you need is an internet connection and a computer. Great for people who travel or check mail at the office and home.
  • Faster than POP -- Full messages are only downloaded to client machine if you want to read them.
IMAP's Limitations
  • Disk space on the server may be limited. Check with your system's administrator.
  • Not all of the mail reader client support files that you may want are available on the IMAP Server. For example, in the Eudora Client: Address Book, Output, and Trash are not available and for example, in Outlook Client: Contact Lists are not available.
  • Synchronizing (refreshing) mail boxes between the IMAP Server and the mail reader client can take some time when mail boxes are very large.
Additional Information For a more detailed discussion of IMAP please visit: