I'm considering adding on IMAP functionality to the server.

I was wondering whats the difference between the two?

POP3 supports a single client connecting to a single mailbox at a time, with no server-side folders, no disconnected operation, and a very simple command set.

IMAP can support multiple clients connecting to mailboxes with unlimited server-side folders, disconnected operation, and some synchronization tools. Most server-side implementations don't support everything IMAP can do, and if your mailboxes are Unix mbox format, it's impossible to achieve certain things.

If you were using qmail's Maildir format and POP3 and IMAP servers which supported that, you could probably support the fancier IMAP stuff. Usually this isn't the case.

Kevin

Ah I see, so multiple users on one mailbox. I see.

By the way you should first make sure that you need IMAP, as there have been a lot of security issues involving IMAP.

Originally posted by SEATi
By the way you should first make sure that you need IMAP, as there have been a lot of security issues involving IMAP.

Well, not really. There have been some security advisories a couple of years ago about a couple of the IMAP daemons. IMAP code is going to be more complex than POP code, but there have been plenty of vulnerabilities in POP daemons in the past as well. I don't think there's a rule of thumb that either one is more likely to be vulnerable.

Kevin

Main Different Between IMAP and POP

POP :
POP was designed to support "offline" mail processing. In the offline paradigm, mail is delivered to a (usually shared) server, and a personal computer user periodically invokes a mail "client" program that connects to the server and downloads all of the pending mail to the user's own machine. Thereafter, all mail processing is local to the client machine.

IMAP :
IMAP is designed to permit manipulation of remote mailboxes as if they were local. Depending on the IMAP client implementation and the mail architecture desired by the system manager, the user may save messages directly on the client machine, or save them on the server, or be given the choice of doing either.

Reference : http://www.imap.org/papers/imap.vs.pop.brief.html


Summary :
POP : all the operation on the mail, will be client side.
The person will download all the mails, and read, delete, and save on the client box.

Since all the mails are downloaded to client machine, you will not be able to check the email from other places , because all the mails been taken off from the server. (there is option you can leave mail on the server), but if you delete mail, it will not do any modification on the server.


IMAP : Operation can be client side or server side

The person will be working on the server side folder structure.

With IMAP, you will be working on the server side, so if you check the mail on one place, it will not be taken away from the server, which will allow you to check from anywhere anytime (because its serverside).

hope that helps

Regarding the security : both has security problems.

another interesting thing with imap is that you don't need to download the attachments
you may see the E-Mail without attachments and decide to download them after
that's why webmails usually uses IMAP

It's almost always pre-installed since most webmail packages use IMAP by default..
wakkow@huamei:~$ telnet redeemedhost.com 143
Trying 65.75.170.50...
Connected to redeemedhost.com.
Escape character is '^]'.
* OK [CAPABILITY IMAP4REV1 LOGIN-REFERRALS AUTH=LOGIN] ephesians.redeemedhost.com IMAP4rev1 2003.339-cpanel at Sat, 7 Aug 2004 10:17:52 -0700 (PDT)
. logout
* BYE ephesians.redeemedhost.com IMAP4rev1 server terminating connection
. OK LOGOUT completed
Connection closed by foreign host.
If thats the server you're referring to, you're all set to go.

By the way, allowing IMAP will cause most of your customers to store all their emails on the server, instead of downloading it to their computers.