Try our new research platform with insights from 80,000+ expert users

KerioConnect vs Microsoft Defender for Office 365 comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Jun 29, 2025

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
6th
Average Rating
7.2
Reviews Sentiment
7.3
Number of Reviews
11
Ranking in other categories
Email Applications (9th)
Microsoft Defender for Offi...
Ranking in Email Archiving
1st
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
60
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 January 2026, in the Email Archiving category, the mindshare of KerioConnect is 3.3%, up from 2.2% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 18.2%, down from 23.1% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Archiving Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 36518.2%
KerioConnect3.3%
Other78.5%
Email Archiving
 

Featured Reviews

MM
Senior Systems Tech/Admin at Samco Software Inc.
A seamless setup ensures smooth communication with comprehensive support
We remain a partner with Sophos and use XG S Firewalls without AWS implementation. We only use Sophos endpoint and Sophos Central. We host some clients on-premise while others we host remotely. The VPN connection is easy and proprietary, so it's not open to any other VPN clients. Communication with other mail servers is seamless. It can communicate with Gmail and Outlook without issues, provided the DNS settings are correct. We monitor our servers and security logs, implementing GeoIP blocking. We frequently block China and India IPs due to brute force attacks on our servers. We have extensive experience with KerioConnect. Backing up and maintaining it is straightforward compared to Microsoft Exchange, making it administrator-friendly. On a scale of 1-10, this solution rates an 8.
Emeka Ndulu - PeerSpot reviewer
Cloud Solutions Architect at a tech services company with 201-500 employees
Improves threat visibility and response while reducing manual tasks and training users against phishing
I appreciate the attack simulation feature whereby I get to train users and educate them on how to identify phishing emails and spam emails, as well as the anti-spam protection. It gives me visibility into my threat environment and threat landscape to ensure that I am one step ahead of any likelihood of threats within my environment. I get to detect it and respond, so the threat intelligence is very effective. Microsoft security solutions save my time. It saves money because once I protect my environment, I don't lose money. It has decreased my detection time and my time to respond.

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 security and privacy because you installed it on your server, within your company premises, not in the cloud."
"The user interface is good."
"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."
"The most valuable features are its ease of use, excellent pricing, and it is platform agnostic."
"We have contacted technical support a handful of times and received some assistance."
"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."
"It's relatively simple to use."
"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 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."
"The coolest feature of Microsoft Defender for Office 365 is its ability to look for phishing emails."
"Microsoft Defender for Office 365 has improved my organization's security. It makes it easier to manage the infrastructure without the help of third-party applications."
"It’s easy to handle integrations, and we don't need a lot of people in our IT team."
"The good part is that you don't have to configure it, which is very convenient."
"There are several features that I consider valuable."
"Since we have started using the solution, there have been fewer compromises."
"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."
 

Cons

"We cannot compete with them because they're fully integrated with their applications."
"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."
"The solution could improve the redundancy because we only have one copy of the Kerio Connect server on our hardware. The next step for us is to move to the cloud and if Kerio does not have a cloud version available they should release one"
"I would like to see better support from their support team."
"You cannot integrate with other services like Google Docs, Google Assistant, Google Calendar, etc."
"The search and archiving documentation capabilities need to be stronger."
"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."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"Microsoft security solutions work as expected. They are constantly updating the solutions to make them better. At the same time, the changes can impact a customer's environment, and we need to adjust settings. Sometimes we aren't aware of the changes, and nothing is pushed from the backend automatically."
"Several simulation options are available within 365, and the phishing simulation could be better."
"The only thing they should improve is the licensing model. They should stop changing it. A year ago, the five features I mentioned were included in one product. Now, three of them are bundled into one product, and you have to pay extra for the other two. I don't mind paying extra, but I don't want them to change it every year or every six months. I need to know what I'm looking at and not worry about it next year."
"The pre-sales cost calculations could be more transparent."
"The phishing and spam filters could use some improvement."
"We need a separate license and we don't know how to get the license that is required."
 

Pricing and Cost Advice

"The pricing is about $3 per mailbox per month."
"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."
"The price of Kerio Connect is better when comparing it to others solutions."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
"The license is expensive because the cost is based on the number of users."
"The pricing has become expensive."
"I know that the product is incredibly expensive."
"The solution could be better by simplifying the business model of their licensing. It was hard to figure out how to get the licensing done for the environment, initially."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"I was working in the government and it was too expensive for us to use our Microsoft products."
report
Use our free recommendation engine to learn which Email Archiving solutions are best for your needs.
881,082 professionals have used our research since 2012.
 

Top Industries

By visitors reading reviews
Comms Service Provider
13%
Computer Software Company
11%
Manufacturing Company
9%
Performing Arts
8%
Computer Software Company
14%
Financial Services Firm
8%
Manufacturing Company
8%
Comms Service Provider
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business10
Midsize Enterprise2
By reviewers
Company SizeCount
Small Business23
Midsize Enterprise10
Large Enterprise31
 

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?
The pricing is very easy to understand. As a partner, we have a monitoring system that informs us when subscriptions expire, allowing us to handle renewals. The pricing is very competitive.
What needs improvement with KerioConnect?
Since KerioConnect is a setup and go solution, everything works on its own. The only administrative tasks required are keeping it up to date, monitoring security logs, and ensuring protection from ...
What needs improvement with Microsoft Defender for Office 365?
The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster.
What is your primary use case for Microsoft Defender for Office 365?
My use case for Microsoft Defender for Office 365 is for email protection, safe links, protection of links, documents, protecting my documents, and protecting attachments. I also use it to conduct ...
 

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: December 2025.
881,082 professionals have used our research since 2012.