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Kerio Mailserver vs. Microsoft Exchange, Hosted Exchange and Google Apps Gmail

© May 2019 Anthony Lawrence

Just in case you aren't a regular visitor here, you should know up front that I am a Kerio reseller and that I am strongly biased against Microsoft Exchange. I took Exchange as one of my certifications way back when I did Microsoft MCSE certification - I disliked it then and I dislike it today.

I will say that Exchange is probably a decent choice for an extremely large company that has lots of in-house IT talent to tend to the beast. If you are General Motors or General Electric, fine. For anyone else, I think Exchange is a foolish choice, both because it will cost you more to begin with and will cost you more in support as you use it.

On the other hand, I'm not necessarily saying that Kerio Mailserver is the right choice for you either. Kerio is a great fit for a lot of companies, but it isn't right for everyone. For example, if you are a strong Linux/Unix person and have the time for administration tasks, there are numerous open source mail servers that might meet your needs perfectly. For some shops, Gmail is a good choice (but see the pricing comparisons below).

As noted, I'm a Kerio reseller and I sell a LOT of Kerio mail servers. However, you need to understand this: I sell Kerio because I like the product and the company. I do not like it because I sell it. That's a very important thing to understand: I've been selling and supporting mail servers for a very long time and I chose Kerio because they have a great product at a great price.

Kerio vs. Exchange

Kerio recently published a new literature piece that compares Exchange features to Kerio features. That reminded me that I've never really written about that here.. so this is a good time to do it.

Platform choice

Exchange obviously runs only on Microsoft operating systems. Kerio Mailserver runs on Microsoft (Server 2000 with SP4, 2003, 2008, XP) but also runs on Mac OS X, Centos, Fedora 7 and 8, Suse and (as of 6.7 which will be out in a few weeks) Debian 4.0 and Ubuntu 8.04! That's choice, and that's very important to me.

Kerio Webmail is also multi-platform. I'll refer you to my Kerio Webmail article for details, but this means your Mac and Linux users don't need to compromise: they get full-featured access to their mail.


Exchange administration is horribly complex. It's very powerful, but it is complicated and confusing - it seems like the panels never end and many choices are counter-intuitive. Kerio administration is clean, quick and very easy to understand and of course if you do run into anything you don't understand, you can just call me (assuming you are my customer) or Kerio. You probably won't be in here much anyway - Kerio requires very little care and feeding.

Of course the Administration tool is cross-platform also. You can run your server on Linux and administer it from Windows or Mac OS X. You can run the server on OS X and administer it from Windows or Linux and so on - you aren't locked in.

Missing Exchange Features

There are a number of things that Kerio includes that Exchange either doesn't have at all or makes you pay extra for. Probably the most important is backup and archiving. Archiving is very important to many companies today for legal compliance, but it's also important for those who want to be sure that customer inquiries were properly handled. Backup is obviously important - what I really appreciate about Kerio backup is the quick restore in case of catastrophe. You can get a replacement mailserver up and running extremely quickly. This also means that it is quick and simple to move Kerio to another machine - even if the new machine is a different operating system! I've moved customer systems from Windows to Linux with as little as ten minutes of downtime!

Exchange can authenticate against Active Directory. So can Kerio, but Kerio also can use Apple Open Directory, Linux PAM or it's own internal database (no directory service needed!). That's flexibility Exchange can't match.

Kerio has two way sync with Apple iCal, CalDAV access from Apple iCal and calendar delegation through Apple iCal. Exchange? Of course not.


Hosted Exchange pricing is incredible expensive. You can shop for the lowest price, of course, but it runs around $100 a year per user. Google Apps Gmail is $50 per year per user. Kerio is far less, even after adding in the costs associated with running your own hardware. The breakdown for that can be found at Google Apps Gmail vs. in-house Mail Server.

In House Exchange is a headache. That's why Hosted Exchange costs so much.

Right choice for you?

Maybe. Fortunately, Kerio provides fully functional demos for 30 days (and I can easily get the demo period extended if you need more time for your evaluation). I can help you set up a demo machine in your own network or provide access to a machine you can play around with. Of course I'm available to help you with configuration and any questions.

Please remember this: I sell this because I think it is an excellent product. I don't pretend that it's a great product because I happen to sell it.

Kerio also has a white paper comparing the costs.

Got something to add? Send me email.

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Inexpensive and informative Apple related e-books:

Take Control of Apple Mail, Third Edition

Take Control of High Sierra

iOS 8: A Take Control Crash Course

Take control of Apple TV, Second Edition

Take Control of iCloud, Fifth Edition

More Articles by © Anthony Lawrence

Thu Mar 19 13:41:43 2009: 5767   TonyLawrence

I forgot to mention that Kerio has migration tools available. I also forgot to talk about price: Kerio is far less cost than Exchange unless Microsoft is playing games with predatory pricing as they sometimes do. For example, we know that sometimes Microsoft will just about give away Exchange to schools and that they include a limited version "free" in some of their products.. well, we all know what those games are about and hopefully you are too smart to fall for them.

Thu Mar 19 13:50:15 2009: 5768   TonyLawrence

Another thing: Microsoft uses a database to store messages. As you can see at articles like (link) that database can be corrupted:

you can also automatically skip and log corrupted mailbox items

Yeah, isn't THAT nice!

Kerio leaves mail as flat text files and builds a separate index for each folder. That means that the messages can't "corrupt" and the index can easily be rebuilt if necessary.

Thu Mar 19 15:27:01 2009: 5770   MikeHostetler

What about Lotus Notes? Or as I call it "Lotus Bloats"? It's what my employer has subjected us to.

I think only large organizations can handle it -- just like Exchange. I think it's better on the server-side than Exchange, esp for large (i.e. International) corporations. The client (both web and thick) is deplorable.

But a small shop installing Lotus Notes? No way. Unthinkable.

Thanks for the notes on Kerio. I knew you sold it and now I see why . . .

Thu Mar 19 15:30:08 2009: 5771   TonyLawrence

I've only experienced a little of Notes - from what I did see, I agree.

Thu Mar 19 16:41:26 2009: 5772   BrettLegree

Hmm, I'll have to look into this further. I'm pitching various ideas to my current company's management (they want to "upgrade" to Vista 64 and Office 2007, yet we are in triage mode due to the financial thing... so I'm saying, maybe we should try things like OpenOffice?)

This looks like a great alternative.

Thu Mar 19 17:30:08 2009: 5773   TonyLawrence

I should mention that another thing I like about Kerio is the constant rate of improvement - they release dot versions regularly and major versions about once a year. Installing new versions is quick and easy.

Sure, once in a while they've had a bad release. They do a lot of beta testing but now and then they've been broadsided. They always fix it quickly and support has never played games about the problem.

Good product, good company.

By the way:

If you are a reseller interested in picking up this line, give me a call ( (link) ) - I'm happy to give you the straight scoop and honest answers to any of your questions. You can feel free to do that even if you are in my geographic area - I'm not afraid of competition and will be happy to help you.

Thu Mar 19 21:56:48 2009: 5774   drag

> so I'm saying, maybe we should try things like OpenOffice?

Well absolutely! At least give a try. OpenOffice.org is not perfect and it's not a acceptable solution for a lot of people... but for lots of other people it's a very nice thing.

The best thing about it is that it does not require your employees to go out and purchase any software on their own. With Microsoft Office your not just buying copies for your own purposes, but everybody that works there is unfortunately faced with reality that unless they get the same version at home then they can't do any work from home, which people will want to do time to time. With OpenOffice you can just hand out CDs like candy and show people were they can download copies on their own.

Whether or not it makes sense to migrate is something you'll have to figure out on your own. There are document compatibility issues, issues with macros that some people depend on, and some UI changes that people will resist and that sort of thing.

The other thing is that migrating to other types of software can yeild good results also. So for example with Office you get Outlook, which you need to work with Exchange.. no other client software will work all that well with Exchange except for the most basic functionality. (Evolution email client on the Linux desktop is just now gaining native Exchange support, but that is something else).

So if your find that it is possible to migrate people away from Exchange, Office, Outlook, Internet Explorer combination to something like Kerio (or any of the other half a dozen very good Linux email solutions), OpenOffice.org, Thunderbird, Firefox can yield not only impressive savings right now, but open doors up for your company later on. All that software is cross platform and can be made to integrate with any number of other services. You can use that stuff on Apple OS X, for example, if people like that. Or you can migrate to Linux desktops, or you can stay with XP much longer then you otherwise could.

While it won't be a good fit for many companies the only way you really can know for certain is to check these things out yourself.

Thu Mar 19 22:56:08 2009: 5775   BrettLegree


I believe that OpenOffice.org is definitely a good fit for us. As I'll be pitching it, we're currently on Office 2000 (yeah, I know... old) and we will have to convert all of our templates & forms etc. to Office 2007 anyway. We will have to train the staff (because the "ribbon UI" is so different).

So why not migrate to OO.org and do the conversion and training for that? Then they can stay with XP until 2014 on the machines that run that long. We can go for some kind of Linux on the new machines we buy. I know that Ubuntu runs perfectly on our standard hardware because I'm writing this on my work laptop (that is running Ubuntu dual-boot with XP).

We could use Outlook Web Access for our email/groupware until we convert to something else. And I know that they are not totally against things outside of the Microsoft suite because there is a Lotus Notes group. Heck, IBM offers a Linux-based solution that uses their OO.org based Lotus Symphony suite including Notes.

Also, if we move to Vista from XP, people will moan about that - while slight, there is a UI change there. Once again, we could customize the WM on Linux to mimic what we have on XP to smooth the transition.

The icing on the cake as I see it is that we get the majority of our funding from our federal government. So I don't think we should really be buying proprietary software with public money.

I fear it may be too late to stop this as I'm not privy to the backroom dealings those in power have made with our software suppliers - but it is worth a shot, and if nothing else, it will get me some visibility. I don't work in IT at all (I'm a chemical engineer) but it is my hobby/passion and if I could transfer into that area until such time as I am self-sufficient, so much the better.

Mon Jun 8 22:41:44 2009: 6475   Jei

I've been administrating Kerio mail server for almost 6 months now... and I'm not really keen about it.

Version 6.1 is very limited. Ok, I'm not a Kerio guru but I miss many features I have in Mdaemon systems.

Antispam features in Kerio are very limited compared to MD. DNSBL finetuning nearly doesn't exist, for auto whitelisting and detailed antispam settings you're in bad luck, same for advanced message filtering using boolean expressions. Well I do miss all this.

In general, black and white list concept (IP/Host/domain level with wildcard support), which is available in many MD functions is almost inexistant in Kerio.

Bandwidth setting, IP caching, queue pre and post-elaboration, security features: all very limited, also.

Last but not least, when defining a new user in MD you get 11 tabs rich of options (for example scripting for not-in-office functions).

Not to talk about many different skins available for Web Clients which MDaemon lets you choose (including an advanced Exchange look and feel).

I would like to list some features I appreciated in Kerio: speed, yes it's fast. Maybe the stats... but they're so limited, not to say useless.

Used to MDaemon it's very hard switching to Kerio.

Obviously it's my personal opinion, maybe some admins do like it, but for my taste it's just too limited.

Just my 2 cents.


Mon Jun 8 23:15:41 2009: 6476   TonyLawrence

6.1??? Current release is 6.7.. if that's not a mistype, you are 3 years behind.

I don't know what you mean by "fine tuning" black lists - can you explain that better? Right now, you can choose how much spam score to add if a black list is hit - is that what you mean?

What is "auto whitelisting" in MD? KMS Spamassasin has AWL but perhaps we mean something different? If you mean setting score based on reputation, KMS does this.

Booleans in filtering? Have you looked at Sieve? (link)

Whitelists and blacklists certainly do exist. Again, we must be talking about different things?

Bandwidth limiting? You can limit connections for services and limit connections from a specific server. I'm not sure why you need more than that, but perhaps you do?

"11 tabs rich of options" of options doesn't mean much without knowing what you specifically need.

Skins? The whole thing is php - do whatever you want with it. I suppose it would be nice if Kerio offered more choices than just changing the logo but that's cosmetics better done by the end user if they really want it.

But "limited"? Yes - definitely. Kerio is designed to be simpler than complex servers like Exchange. Still, a lot has been added since 6.1 so that may be part of your problem.

One thing Kerio definitely needs is an API. That would let resellers like me more easily answer the needs of people like you.

Contact me directly if you haven't upgraded to 6.7 because of price. I may be able to help.

Mon Jun 8 23:19:59 2009: 6477   TonyLawrence

You might want to review (link) to see what's been changed since 6.1

Wed Jun 10 10:55:38 2009: 6484   jei

Hi Tony,

yes you're right, the version I use is 6.6.2.

Let me find a moment to get both mail server on my notebook and I will detail the features I already mentioned.

Thanks for your answer.


Wed Jun 10 11:52:47 2009: 6485   TonyLawrence

6.6.2 is almost current, so that's good. I look forward to your comments.

If they are long, I'd rather publish them as a separate article and put a link to them here.

Wed Jul 22 17:32:08 2009: 6670   anonymous

we're on kerio 6.6.2. i've used exchange as an end-user in the past.

i miss a couple end-user features - most notably an audible notification of new email, and search. as far as i can tell, search only searches words in the subject line? i'd really like search to be able to search the entire body of the email..... is that coming any time soon? there are also a few quirks related to setting up appointments and revising appointments, but all in all it is working ok. just seems a bit "unfinished" after using exchange, or even my personal gmail account.

Wed Jul 22 18:02:19 2009: 6671   TonyLawrence

I think "unfinished" is fair. The Outlook Connector is a work in progress.


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