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Feature: Mail & Messaging

PostPath cracked Exchange protocols for Postfix-based mail server

By Tina Gasperson on July 30, 2008 (7:00:00 PM)

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PostPath is a drop-in Microsoft Exchange alternative based on the open source Postfix MTA. PostPath director of product management Sina Miri calls PostPath the "only" drop-in Exchange replacement, and he says that ability is the reason why his company makes PostPath available only with a proprietary license, despite its open source roots.

Miri charged PostPath engineers with creating a mail server that was comparable to Exchange, but was less expensive, more flexible, and able to run on Linux servers. Not only that, but PostPath needed to be compatible with Microsoft Exchange, meaning that the network had to work with PostPath with no plugins, add-ons, or rewritten protocols. Miri says PostPath accomplished its goals by building PostPath from Postfix, the popular MTA created by Wietse Venema and distributed under the terms of the IBM Public License (IPL), but with a crucial addition.

The pi├Ęce de r├ęsistance in the creation of PostPath was the compatibility component. "There is no plugin or middleware required to use PostPath," Miri says. "When you drop PostPath in, the network thinks it is talking to an Exchange server. This makes it very easy for people to evaluate and buy and migrate. It's a lot easier to go from Exchange 2003 to PostPath than to go from Exchange 2003 to Exchange 2007. That's like doing a completely new installation." Microsoft calls migration from Exchange 2003 to 2007 a "transition" that happens in "several phases." In contrast, PostPath's claim to fame is that it uses Exchange's own protocols to achieve full compatibility even with other Exchange servers on the network, making it possible for Exchange 5.5 or 2003 users feeling the squeeze from Microsoft to easily move to an alternative mail server infrastructure.

Gartner analyst Matt Cain says PostPath really does drop into the network. "They can fit nicely in Active Directory, and that's one of the primary things folks are concerned about. I don't know about the [ease of] migration, but I would say that it is pretty difficult to migrate from Exchange 2003 to 2007, so it wouldn't be all that hard to make it easier [with PostPath]."

Exactly how PostPath was able to unlock Microsoft's protocols will remain a secret, because PostPath is proprietary. "If you give that away, a lot of the value of PostPath is going away," Miri says.

Postfix author Venema doesn't express any angst over the fact that a proprietary product borrows so liberally from open source. "They can do what they want to with their own source code," he says. PostPath's modifications to Postfix and other open source code are posted at the company's Web site for free download.

If Microsoft has a problem with PostPath reverse-engineering its protocols, it hasn't told PostPath, Miri says. Microsoft officials declined to comment when asked if they minded. But PostPath is extra careful never to hire anyone who has worked at Microsoft before, "so there's no risk of somebody thinking we came by it unfairly."

Basing PostPath on open source has been good for the company, Miri says. "You get better support from using open source tools than with commercial products. If you come across some issues or questions, if you use open source there's more information available to you much faster than using a commercial product. I don't see how a company even as big as Microsoft can compete with the service and support [from open source products]."

Tina Gasperson writes about business and technology from an open source perspective.

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on PostPath cracked Exchange protocols for Postfix-based mail server

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good for the goose?

Posted by: Anonymous [ip: 12.202.177.210] on July 30, 2008 07:20 PM
Interesting that Miri of Postpath sings the praises of open source ... yet their product is proprietary. Isn't what's good for the goose (postpath) also good for the gander (postpath customers)?

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 216.70.10.75] on July 30, 2008 08:05 PM
"Sina Miri calls PostPath the "only" drop-in Exchange replacement, and he says that ability is the reason why his company makes PostPath available only with a proprietary license"

I'm not sure I see the logic there. Why should the fact that it is the 'only' one lead to it needing a proprietory license?

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 76.119.12.163] on July 30, 2008 09:31 PM
Why should anyone trust their development process and security practices any more than Microsoft? Closed code? WTF? I work hard to free myself from any prorpietary garbage in my work flow and I'm going to drop in this junk? After all my hard work to be open source? This doesn't seem to fulfil a need enough to justify it, as some other closed source apps might. For instance, certain video editing applications or photoshop maybe, but one can put those on non-networked boxen and not worry as much about security. Gotta love these guys who gush open source lip service in their their marketing schpiel, but then turn around and choose the least creative business model possible when it comes to their own code. Yes this is a case of supply and demand, so who can blame them? But the customer is at the mercy of the company's decision to support this product. It could go away forever tomorrow and that would be that. Glad I don't need it.

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 141.123.123.100] on July 30, 2008 09:42 PM
Yet another Exchange replacement? Suuuuuure...I've seen plenty come and go in the last 10 years, and pretty much they all...well, go...Exchange isn't a mail server, so anyone who sells you a replacement on that premise is selling you snakeoil. If they don't understand the basics of the product, they certainly can't replace it.

Oh, and 2003 to 2007 is a nightmare? Huh, we did our 14,000 users in about two months and they didn't even know. Well, aside from all of the new features, that is.. :)

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Not open source? Not interested.

Posted by: Anonymous [ip: 66.114.78.90] on July 31, 2008 04:19 AM
If you're not breaking away from proprietary software then there's no point in making a change. In any case, the feature set of Exchange sucks, and replacing Exchange with a half baked clone-of-Exchange is simply the wrong answer for most organizations. A lot of people are finding that the workflow and feature set of Citadel [http://www.citadel.org] helps them get their worlds organized far more sanely -- and it's end-to-end GPL code. Give it a try.

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 62.58.77.30] on July 31, 2008 10:23 AM
"the "only" drop-in Exchange replacement" - hardly, ever heard of Zarafa?
http://www.zarafa.nl/

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Re: PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 81.57.42.108] on July 31, 2008 05:53 PM
Zarafa is also an Exchange replacement, but not "drop-in" (at least, not in the sense Postpath seems to imply on their website) : Zarafa uses their own protocol, not the native Exchange protocol.

Which is good in some aspects :
- Data is transported on SOAP over http/https, so easy to firewall and proxy (as opposed to Exchange RPC protocol, wich require the server to connect back on a client' random port to send notifications....)
- It's more flexible (you can teach him you're own ldap schema for auth, use ssl everywhere, ...)

But this is bad in other aspects :
- You need to install the Zarafa Outlook plugin on every client machine (this take a lot of time). For every major update of the server, you have to upgrade every clients (which is very problematic for large installations).
- And indeed, the Linux/MacOS/... opensource exchange clients implementations (like the plugins for Evolution) won't work at all with it (you have to fallback with their imap gateway)

Beside, Zarafa has *very hard time* to handle large "stores" (mailboxes). A single user moving lots of mails can leave long running locks on the database, which prevents all other users to work with their mails. And as a sysadmin, that mean having the big boss shouting on my shoulders...
I currently administer a zarafa server at my compagny, and am looking for any replacement that would work well on Linux because of such bugs and low scalability problems.
In that respect, Postpath looks better designed, but it would be insane to migrate right now on such a young product.

So, both being unfixable (by the community) proprietary products, I wouldn't encourage any of them. Esp. having tested Zarafa in a real, production, environnement.

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exchange 2003->2007 is really easy

Posted by: Anonymous [ip: 84.202.192.164] on July 31, 2008 09:57 PM
Exchange 2003-> 2007 transition is actually very easy. As long as you introduce Exchange 2007 as a new server everything is done on-the-fly. You move the mailboxes to the new servers(VERY simple with the management tool). When the client connects to the old server it updates the configuration and then connects to the new server. No big deal, and you can do the transition without any downtime..

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 203.94.186.202] on August 04, 2008 12:11 AM
Honestly, every time a group of developers manage to crack the exchange protocol or build an exchange replacement it inevitably ends up being proprietary code. In my book, paying for such code based on open source software just encourages these people to keep up such silly practices.

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PostPath cracked Exchange protocols for Postfix-based mail server

Posted by: Anonymous [ip: 192.168.7.91] on August 04, 2008 05:40 AM
Postpath appears to be using the webui from another Exchange killer, Zimbra, perhaps in violation of the ZPL/YPL. Do a google search for Postpath and Zimbra, on the plus side it seems like an innocent enough mistake...

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