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KerioConnect vs Microsoft Defender for Office 365 comparison

 

Comparison Buyer's Guide

Executive Summary

Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Categories and Ranking

KerioConnect
Ranking in Email Archiving
8th
Average Rating
6.8
Reviews Sentiment
7.3
Number of Reviews
10
Ranking in other categories
Email Applications (9th)
Microsoft Defender for Offi...
Ranking in Email Archiving
1st
Average Rating
8.4
Reviews Sentiment
7.1
Number of Reviews
52
Ranking in other categories
Email Security (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (10th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of June 2025, in the Email Archiving category, the mindshare of KerioConnect is 1.5%, down from 2.6% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 31.3%, up from 15.5% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Archiving
 

Featured Reviews

David Bloomer - PeerSpot reviewer
Lightweight, simple, and robust; easy to maintain and doesn't require a lot of system resources to run
Kerio Connect does as advertised, so there are no real issues with the product itself. It's developed regularly, so there are constant updates. Possibly, the support and development have lessened since they've sold the company, but as far as the product itself is concerned, there isn't anything that I would suggest needs improvement. If I'm being picky, Kerio Connect uses a proprietary, mappy atom for Outlook, and it would be nice if they used a native mappy connection instead, but that's the only additional feature that I would like to see in its next release. If they have native Outlook map integration, that would be great, but other than that, it's got all the functions that I think a mail server should have.
Tolu Omolaja - PeerSpot reviewer
Great URL scanning and attachment scanning, but I would like more proactive threat analysis
The two main features that prove most beneficial for us are URL scanning and attachment scanning. URL scanning involves an automatic scan of links and emails. When a user clicks on a link within an email, the system promptly checks the link's safety. If the link is deemed safe, access is granted automatically. However, if it is flagged as unsafe, we receive feedback and notification to caution us about the potentially harmful link. At this point, we are presented with the option to proceed or return. I have personally witnessed the system identify a few unsafe links, making this the primary advantage of using the solution. The second crucial aspect is the scanning of attachments. When an email containing an attachment arrives, we receive a notification of the new email, along with information that the attachment is being scanned for threats. This additional layer of security provides peace of mind for our organization. While Microsoft Defender for Office 365 offers numerous features, these two stand out as particularly impressive and valuable to us.

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Pros

"The most valuable features are its ease of use, excellent pricing, and it is platform agnostic."
"We use the solution as a mail server. It connects with Outlook and is used for calendaring and similar tasks."
"Kerio Connect is secure, flexible, and easy to control from the user interface. It has many security features able to be controlled from one place, such as anti-spam. I have found it very convenient. Additionally, you can analyze log files and share folders which is helpful."
"It's relatively simple to use."
"KerioConnect has integration with 365. We can use Outlook, which has its client and can be used with Apple devices. It integrates with the App Store and Microsoft Office. It has a smart router. The spam filtering and antivirus are good."
"The most valuable features are security and privacy because you installed it on your server, within your company premises, not in the cloud."
"We have contacted technical support a handful of times and received some assistance."
"The solution is easy to maintain, unlike Exchange. It's easy to create multiple domains and back up and restore if needed. It also has good security features like anti-spam and antivirus."
"The technical support is good and quick to resolve issues."
"The stability of Microsoft Defender for Office 365 is fantastic."
"Microsoft Defender for Office 365 helps people to work remotely. It is a secure solution. We don't need to use our company's computers or get VPN connections to the networks. I can control how they share screens and what they send to the devices. It keeps our organizations confidential and sensitive information safe."
"It has significantly decreased my time to detection and response."
"The basic features are okay and I'm satisfied with the Defender."
"Overall, I would rate Microsoft Defender for Office 365 at a ten."
"The solution is very easy to use. All you have to do is to assign the license to the end-user and it's done. The customer will only have the feature activated, and the solution will monitor the emails to determine if they are a threat or not."
"The benefit that stands out to me is the ability for multiple individuals to collaborate simultaneously within the same document. Additionally, there is the option to save the document directly in the integrated OneDrive or SharePoint."
 

Cons

"Most of our clients use Outlook and Kerio Connect. Occasionally, Kerio can be a bit slow. They could make it faster to get onto the web interface without so much load time. It's just slow with Outlook, however, for some reason."
"Having a native Outlook map integration would make Kerio Connect better."
"KerioConnect is stable as long as you use a strong password."
"You cannot integrate with other services like Google Docs, Google Assistant, Google Calendar, etc."
"It could be simpler to use and install, but I still wouldn't use it because there isn't a compelling use case."
"We are considering switching to Microsoft Exchange. One reason is that it doesn't improve our workflow and doesn't integrate well with Microsoft 365 applications."
"I would like to see better support from their support team."
"The search and archiving documentation capabilities need to be stronger."
"Microsoft Defender for Office 365 should be more proactive."
"Specifically, within Microsoft Defender for Office 365, I want it to improve the DLP capabilities."
"It would be better if it were more scalable. It depends on the architecture, but we would like to make it more scalable for both data centers."
"There is a different console for different things; I just want one consolidated console."
"The certification training for Defender for 365 needs to be deeper and incorporate Sentinel. I took all the security courses except one, and Sentinel isn't included."
"One area for improvement is support, in terms of being able to reach them and, especially, technical support for configuration."
"The XDR dashboard has room for improvement."
"This product's effectiveness could be improved, in terms of detecting unwanted spam or even malware between the emails, compared to other products."
 

Pricing and Cost Advice

"The pricing is about $3 per mailbox per month."
"The price of Kerio Connect is better when comparing it to others solutions."
"KerioConnect has a first-time cost and yearly subscription. It is not expensive."
"The solution's pricing depends on how long you plan to keep it because you pay on a per-year basis. You might have a one-time setup cost for something like Microsoft Exchange or a Linux mail server. I'd say this solution is expensive on a per-year basis, almost 2000-3000 dollars annually. It doesn't seem to pay off yet, so we're considering switching to another product."
"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"For licensing, it's usually a yearly package for customers who are subscribed to Office 365, but they can also pay on a monthly basis."
"While Microsoft Defender for Office 365 necessitates pricier E3 or E5 subscriptions, the extensive functionality offered by these licenses across various Microsoft products justifies the investment."
"It is much more expensive than using another solution because we have had to include some options and upgrade our license."
"Defender is a little bit more expensive as compared to others. We are in the manufacturing environment. So, we don't have a high budget for all of our endpoint devices. Its cost is a major concern for us."
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Top Industries

By visitors reading reviews
Computer Software Company
16%
Comms Service Provider
13%
Government
7%
Retailer
6%
Computer Software Company
16%
Financial Services Firm
9%
Manufacturing Company
8%
Government
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
 

Questions from the Community

What do you like most about KerioConnect?
The most valuable features are security and privacy because you installed it on your server, within your company premises, not in the cloud.
What is your experience regarding pricing and costs for KerioConnect?
KerioConnect has a first-time cost and yearly subscription. It is not expensive.
What needs improvement with KerioConnect?
KerioConnect continues to improve with regular updates throughout the year. They must be added to the roadmap, which requires approval. In larger organizations, the server's capabilities and the da...
What do you like most about Microsoft Defender for Office 365?
Threat Explorer is an invaluable tool for me, and it plays a crucial role in helping me discern the origins of various email campaigns, pinpointing where they emanate from, and identifying the indi...
What is your experience regarding pricing and costs for Microsoft Defender for Office 365?
Microsoft is quite affordable with a lot of features available for any size organization.
What needs improvement with Microsoft Defender for Office 365?
Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published. It's essential to enhan...
 

Also Known As

No data available
MS Defender for Office 365
 

Overview

 

Sample Customers

Southern Tier Brewing Company, Innotta, Baustoff + Metall, Hamifleurs, Chanson TV, Ryman Stationery
Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Find out what your peers are saying about KerioConnect vs. Microsoft Defender for Office 365 and other solutions. Updated: May 2025.
857,028 professionals have used our research since 2012.