From POP3 To IMAP-What Solutions Are There? 18
Rhyder asks: "Users were once-happy with a POP3 client and their single desktop or laptop. As the productive portion of the user-base (20% do 80% of the work) moves up in knowledge, implementation and expectations, they simply realize that there should exist something better than a POP3 client. The upper 10% further realize that there must exist an open standard, something beyond Lotus Notes and MS Exchange. Should I implement a GNU server or a commercial server? I refrain from mentioning any packages here, as I do not want to bias a selection. But really, what is the best approach for an IMAP4 server with the posibility of adding on Radius Authentication, Web-based e-mail, possibly a directory service as well? Should a Sendmail core be implemented, or at least used as an MTA? Oh yeah, which OS - Solaris, Linux, BSD, or something else?"
Re:Why not? (Score:2)
I'm dealing with a similar situation; I've been looking for open source solutions for a while, and so far, nothing has emerged that's integrated enough to consider.
Requirements (and possible point solutions)
- News server (inn)
- SMTP mail backbone (sendmail)
- POP3 and IMAP4 mail servers (qpopper, cyrus, UW)
- MS-like "shared folders" (Samba)
- group calendaring/scheduling w/Palm conduit (?)
- forms management and workflow (?)
(think purchase requests, expense reporting)
- shared addressbook (something IMAP based?)
- assignable to-do or tasks (?)
- Web client access to all of this
- virus scanning (procmail?)
- Integration among them (e.g. calendar/meeting
requests show up in email, click reply,
calendar entry shows up in your calendar)
- and of course, some way to manage it all.
MS Exchange, Lotus Notes, and HP OpenSomething (OpenMail?) are all candidates in the commercial world.
In the open source world, I think it would currently be a lot of work to put something like this together from the various pieces.
Help me be wrong!
Re:Why not? (Score:1)
whoops -- I meant LDAP based, of course.
Re:Why not? (Score:1)
Check out WorldPilot (Score:1)
How many users? Where? (Score:3)
Should you go with IMAP instead of a proprietary commercial maessaging system? Depends. If all you want is e-mail and adddressbooks, an IMAP server and an LDAP server will work just fine, and there are plenty of free web clients for remote access that you can chuck on top of any HTTP server.
But unless you're in an all *nix environment that can use iCal or the KDE or GNOME PIMs, if you plan to do group calendaring, scheduling, shared task lists and so forth, you're better off biting the bullet and going with something commercial, in which case I'd side with Domino/Notes mostly because they have a native Mac client for the non-email functionality, and a web inetrface that even extends to your custom apps, so you're not stuck with putting everyone who needs the scheduling but not on Win32 on feature-restricted webmail (contrast: Exchange). Also, you have a wide range of OSes you can run the server on (from Netware and WnNT to Linux, Solaris and OS/400). The Sun/Netscape/iPlanet suite is a political compromise, since the mail server is pure IMAP.. but as a groupware platform, it ain't no Notes.
Kick those IMAP zealots in the teeth unless they understand they're not going to be able to do any PIM-based, Palm-syncable group calendaring in a heterogeneous environment with Free Software. There are solutions, but no integrated or cross-platform ones. (Insert big asterisk for StarOffice, but that's another story).
That said, my experince has been that of the two free IMAP servers out there, Cyrus outperforms UW-IMAP. The latter puts each "mail folder" in a single mbox-style file, which is nice for POP-IMAP-Pine interoperability, but it also means crummy performance on large mailboxes, since an IMAP server has to "grep" for a full set of message headers every time a folder is accessed. Cyrus seems to do things more efficiently.
What OS do you want to run it on? Unless you're going to be supporting several thousand users or more, use anything you're comfortable with. Linux is plenty fine. BSD is fine. [Insert Un*x flavor here] is fine. If you've got a mainframe that can run it, that's fine too. NT would probably be okay, too, if you don't mind rebooting your mail server once a week or so to prevent memory leaks. If you're doing this for a large university or a large company with 10,000 or more users, the OS matters a bit more if you want to go with a few large servers rather than segmenting your mailboxes onto a bunch of smaller ones. Ah, politics.
Much more important than OS is the way you organize your disks and that you have enough RAM for the job. Assume 2-4MB of RAM will be in use for each user connected to the IMAP server, and since IMAP stays connected until told otherwise, that could mean quite a few people connected all day. As for disks, the faster the better, and if you have a separate drive (or striped drives) for the mail, all the better.
If you're in a mixed-OS environment, I'd go with a PAM-compliant Unix or with Linux. Both Cyrus and UW-IMAP can authenticate against pretty much anything, thanks to the wonder that is PAM. NIS? Fine. An NT domain via pam_smb? Fine. LDAP? Novell? Radius? Ditto.
All of the Above (Score:2)
Cyrus also has support for shared IMAP folders, NNTP->IMAP gateways, server-side filtering through sieve.. very cool stuff.
Re:How many users? Where? (Score:3)
True. You can get UW-IMAP to perform a bit closer to Cyrus by forcing it to use "mbx" mailboxes rather than "mbox" mailboxes. I believe mbx is a slight variation on mbox, with an index to make things faster. Works with pine, too.
Sounds like your topic should be groupware. (Score:1)
Web collaboration software is a neat idea and one that I think will be a bit more prominant in the not so distant future.
My personal pick is TWIG. http://twig.screwdriver.net I believe is their URL.
Retrieving from POP into IMAP (Score:1)
I've never used IMAP, but I'm assuming it provides similar funtionality to Outlook's ability to create folders on both the Exchange server. I use this extensively between my desktop and laptop.
Re:Retrieving from POP into IMAP (Score:1)
I used to use a bunch of scripts, a portable hard drive, directory sync software, etc.
By I found that the more straightforward solution, buying a sufficiently powerful notebook and getting rid of the desktop, works a lot better and is much less work to keep everything gong.
Nobody mentioned Courier IMAP (Score:2)
I use Courier IMAP and Qmail. Qmail provides the POP3 support (for migration), and Courier IMAP does all the external authentication bits you'd need, including IMAP over SSL. I've found Courier IMAP to be extremely stable and fast and works well with my setup (heterogenious environment with pine, Outlook and NS Communicator clients). Currently imapd + couriertcpd are using just over a Meg of RAM.
However, as others have mentioned, it sounds like you're also looking for groupware features. In that case you may be interested in the non-free HP OpenMail, which provides MS exchange server emulation, for things like shared folders, Calendaring and all the other Outlook things.
This is something I think the free software community should be working on - Exchange server interoperability. I hear the Gnome project is working on it with their PIM, but it doesn't sound to me like they're attacking the right angle.
A plesant configuration.. (Score:1)
For and IMAP server I use the Courier IMAP [inter7.com] package. It is a small, featurefull server which support Maildir. It would probably be fine for your needs as it has a very well designed authentication model which supports LDAP (among other things). Courier is faster and smaller than UW-IMAP and Cyrus.
Finally I use TWIG [screwdriver.net] for Webmail. It supports IMAP mail, calendars, contact lists, newsgroups, etc. It is also based on PHP (yay!).
It is a very nice setup, and wasen't too hard to setup. Oh, I forgot to mention that the server is FreeBSD 3.4.
Cyrus/Qmail solution (Score:1)
I built a webbased management interface for it that allows administrators to add and modify accounts. Cyrus' folder sharing options are very cool indeed. The systems authenticates it's users against an NT domain using the Cyrus option to run an external 'pwcheck' process.
Qmail is very flexible and works very well together with Cyrus. I have a virusscanner (NAI) that scans all incoming messages before they are passed on to the user's mailbox.
All in all these components make for a very flexible solution, but IMO it is necessary to build a user friendly frontend for them, otherwise I would have had to do all administration myself.
Unfortunately Cyrus is not GPL'd or we would have been able to sell plug and play MS-Exchange killer Linux boxes with it.
What we do for 50,000 Users.. (Score:1)
To keep things short, I'll tell you where we ended up
As for the question of IMAP vs. POP, I think you really need to look at the practicalities of offering one over the other. I won't go over it all again (I know somone else has posted on the same line) but IMAP is not really the way to go for an ISP/dial-in/remote-user environment. I think it perhaps it was even on www.imap.org that I found a quote stating that IMAP was best utilised in a University environment.
I know I'm not really answering your question, but I thought you might be interested to see a path someone has taken.
Remote POP to local IMAP (Score:2)
Yes, there is a solution. It's called fetchmail [tuxedo.org], and I was amazed at how easy it was to get it set up properly.
IMAP Solution (Score:1)
Well Said. Let me add a few things... (Score:1)
Regardless of which IMAP server you use, I would reccomend that you still make a POP3 server available. If you go with Cyrus, I'm not sure if this is possible but I know you can mix UW IMAPd and other POP3 servers.
For POP3, I highly, highly reccomend cucipop. Search for it on Freshmeat. If you're commercial though, you might want to review its licensing terms. Cucipop's advantage over qpopper is that Cucipop runs as a standalone daemon. This makes a *huge* speed difference on lightly loaded POP3 servers and an unbelievable speed difference on a heavily-loaded server. When I switched to cucipop, I actually got comments from users who noticed how much faster "netscape checked mail".
As far as Windows-based clients go... I like Eudora myself. It's IMAP support is kinda funky--it stubbornly insists that each server be a subfolder of your main inbox folder. I don't like huge nests of mail folders so I find this annoying. To get around this, I just use POP3.
Outlook is a bloated pig and seemed difficult to customize. Outlook's calendaring is nice but there's probably a standalone calendaring app that does just fine. Netscape Communicator does IMAP nicely but I don't like the lack of customization options.
For *nix clients, pick your poison. I'm sure some folks here will flame this but if your *nix clients have good NFS file locking support, you can't beat exporting
For MTAs, take a look at Exim [exim.org]. Exim is very fast and I found it a bit easier to configure than Sendmail. Exim's filtering capabilities are top-notch and you don't have to have a PhD to implement them.
For OSes, I'm a FreeBSD bigot so I'd urge you to give FreeBSD a try. I used Linux starting in 1994 but switched to FreeBSD when I got tired of patching up the million and one r00t exploits that my Linux boxes were vulnerable. FreeBSD is fast and very stable--our boxes have 300+ day uptimes. They would have 700+ day uptimes had we not brought them down for RAM upgrades last year.
buena suerte!
chris
Re:Check out WorldPilot (Score:1)
beyond the first screen(i.e login and password
any pointers