KerioConnect vs Microsoft Defender for Office 365 comparison

GFI and Microsoft are both solutions in the Email Archiving category. GFI is ranked #7 with an average rating of 10.0, while Microsoft is ranked #1 with an average rating of 8.5. GFI holds a 3.3% mindshare in EA, compared to Microsoft’s 10.7% mindshare. Additionally, 62% of GFI users are willing to recommend the solution, compared to 96% of Microsoft users who would recommend it.

KerioConnect

Read 11 KerioConnect reviews

2,176 Views
457 Comparison Views

62% willing to recommend

Microsoft Defender for Offi...

Read 61 Microsoft Defender for Office 365 reviews

17,515 Views
1,752 Comparison Views

96% willing to recommend

KerioConnect

Microsoft Defender for Offi...

Comparison Buyer's Guide

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Executive SummaryUpdated on Jun 29, 2025

KerioConnect and Microsoft Defender for Office 365 compete in the email security and collaboration space. Microsoft Defender for Office 365 appears to have an upper hand due to its robust security features, which justify the higher cost.

Features: KerioConnect focuses on email, calendar, and contact management, offering antivirus protection and cross-platform support. Microsoft Defender for Office 365 enhances security with advanced threat protection, anti-phishing, and investigation features.

Room for Improvement: KerioConnect could enhance its security capabilities, integration with third-party apps, and scalability for larger enterprises. Microsoft Defender may improve its user interface, reduce complexity in configuration, and optimize resource usage during deployment.

Ease of Deployment and Customer Service: KerioConnect is straightforward to deploy and offers responsive customer support. Microsoft Defender for Office 365 benefits from seamless integration within the Microsoft ecosystem and robust support infrastructure due to its larger network.

Pricing and ROI: KerioConnect is cost-effective and appeals to small and mid-sized businesses looking for communication solutions. Microsoft Defender for Office 365, while more costly, offers substantial ROI through enhanced security features suitable for larger enterprises prioritizing security.

To learn more, read our detailed KerioConnect vs. Microsoft Defender for Office 365 Report (Updated: August 2026).

Buyer's Guide

KerioConnect vs. Microsoft Defender for Office 365

August 2026

Download the complete report

Helped 908,800 peers since 2012

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

7th

Average Rating

7.2

Reviews Sentiment

7.3

Number of Reviews

Ranking in other categories

Email Applications (8th)

Microsoft Defender for Offi...

Ranking in Email Archiving

1st

Average Rating

8.4

Reviews Sentiment

6.8

Number of Reviews

Ranking in other categories

Email Security (2nd), Advanced Threat Protection (ATP) (3rd), Microsoft Security Suite (9th), Secure Email Gateway (SEG) (2nd)

Mindshare comparison

As of August 2026, in the Email Archiving category, the mindshare of KerioConnect is 3.3%, up from 0.9% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 10.7%, down from 35.9% compared to the previous year. It is calculated based on PeerSpot user engagement data.

Email Archiving Mindshare Distribution
Product	Mindshare (%)
Microsoft Defender for Office 365	10.7%
KerioConnect	3.3%
Other	86.0%

Email Archiving

Featured Reviews

Marcelino Mongcal

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.

Read full review

Emeka Ndulu

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.

Read full review

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."

"Kerio Connect is secure, flexible, and easy to control from the user interface."

"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."

"This solution is our SMB alternative to Exchange, installed for more than forty SMB customers in a Linux environment with all of the collaboration features."

"The user interface is good."

"Backing up and maintaining it is straightforward compared to Microsoft Exchange, making it administrator-friendly."

"We have contacted technical support a handful of times and received some assistance."

"What I like most about Kerio Connect is that it supports ActiveSync, and that is its most critical feature. The solution is also a nice, simple, robust, and stable mail server."

More KerioConnect pros

"We use Microsoft Defender for its ability to integrate with existing business technologies, which is beneficial for protecting business areas."

"The product is not resource-intensive."

"There are several features that I consider valuable."

"The initial setup is straightforward. You just add the license, click it, and then you can set up the rules. It is quite simple."

"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."

"Defender enables us to secure all 365-related activity from a single place. It gives us visibility into everything happening in Outlook, protecting us against phishing and other email-based threats. Defender helps us detect any suspicious behaviors."

"It also gives me good visibility because, with Defender, I'm using a Microsoft product to defend Microsoft products. The integration was really seamless and I have wide visibility because it picks up almost everything. Literally, I can see almost every activity that happens, from the e-mail to the workstation itself."

"Technical support is very good. They are knowledgeable and respond quickly."

More Microsoft Defender for Office 365 pros

Cons

"I would like to see better support from their support team."

"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."

"KerioConnect continues to improve with regular updates throughout the year. They must be added to the roadmap, which requires approval."

"The search and archiving documentation capabilities need to be stronger."

"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."

"It could be simpler to use and install, but I still wouldn't use it because there isn't a compelling use case."

"You cannot integrate with other services like Google Docs, Google Assistant, Google Calendar, etc."

"We cannot compete with them because they're fully integrated with their applications."

More KerioConnect cons

"This is quite an expensive solution and understanding the pricing model and features is quite complicated and it can, in fact, be a nightmare when dealing with Microsoft."

"Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published."

"Microsoft needs to broaden its global support presence by establishing teams of subject-matter experts in all regions."

"The GUI is sometimes slow to fetch the device report and could be improved."

"From a development point of view, if I wanted to do development on my actual machine where Defender is, the organization can set certain policies or Defender makes that prohibitive."

"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."

"Specifically, within Microsoft Defender for Office 365, I want it to improve the DLP capabilities."

"There is a different console for different things; I just want one consolidated console."

More Microsoft Defender for Office 365 cons

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."

"It is much more expensive than using another solution because we have had to include some options and upgrade our license."

"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."

"The pricing is normal. Considering its popularity, it's not overpriced."

"I know that the product is incredibly expensive."

"From the pricing point of view, like any other product in the market, there is scope for negotiation."

"Defender for 365 comes in various plans and licenses, along with other Microsoft security solutions. Purchasing this kind of package or security bundle gives good value for money, and that's what I recommend."

"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."

"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."

More Microsoft Defender for Office 365 pricing and cost advice

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Top Industries

By visitors reading reviews

Comms Service Provider

13%

Manufacturing Company

11%

Construction Company

Retailer

Computer Software Company

11%

Manufacturing Company

Financial Services Firm

Comms Service Provider

Company Size

By reviewers

Large Enterprise

Midsize Enterprise

Small Business

By reviewers
Company Size	Count
Small Business	10
Midsize Enterprise	2

By reviewers
Company Size	Count
Small Business	24
Midsize Enterprise	11
Large Enterprise	32

Questions from the Community

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.

See all answers

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 ...

See all answers

What is your primary use case for KerioConnect?

Small medium-sized businesses are our primary focus, particularly in warehouse distribution and retail sectors. We are a reseller and purchase directly from Sophos.

See all answers

What is your experience regarding pricing and costs for Microsoft Defender for Office 365?

My experience with pricing, setup, and licensing is that it's actually quite reasonable even on the licensing side as a standalone product. It's very competitive compared to what competitors are ch...

See all answers

What needs improvement with Microsoft Defender for Office 365?

I think Microsoft Defender for Office 365 can be improved by creating more educational pieces about not just looking for malware. We are seeing a lot more malware-less emails that Defender for Offi...

See all answers

What is your primary use case for Microsoft Defender for Office 365?

My main use cases for Microsoft Defender for Office 365 include email hygiene.

See all answers

Comparisons

Microsoft Exchange vs KerioConnect

Compared 16% of the time

Zimbra Collaboration vs KerioConnect

Compared 11% of the time

Open-Xchange vs KerioConnect

Compared 9% of the time

IceWarp vs KerioConnect

Compared 9% of the time

Proofpoint Intelligent Compliance Platform vs KerioConnect

Compared 7% of the time

More KerioConnect Competitors

Proofpoint Email Protection vs Microsoft Defender for Office 365

Compared 6% of the time

Check Point Email Security (formerly Harmony Email & Collaboration) vs Microsoft Defender for Office 365

Compared 4% of the time

Mimecast Advanced Email Security vs Microsoft Defender for Office 365

Compared 4% of the time

Cisco Secure Email vs Microsoft Defender for Office 365

Compared 3% of the time

Barracuda Email Protection vs Microsoft Defender for Office 365

Compared 3% of the time

More Microsoft Defender for Office 365 Competitors

Product Reports

Buyer's Guide

KerioConnect

July 2026

Download KerioConnect product report

Buyer's Guide

Microsoft Defender for Office 365

July 2026

Microsoft Defender for Office 365 report

Download Microsoft Defender for Office 365 product report

Also Known As

No data available

MS Defender for Office 365

Overview

KerioConnect delivers easy-to-use and secure email, calendar, and collaboration tools compatible with Office, Apple, and ActiveSync. Cost-effective and flexible, it suits on-premise installations, especially for SMBs seeking privacy and security.

KerioConnect offers a comprehensive email server experience with minimal resource needs and effective spam filtering. Compatible across platforms, it supports Outlook, enabling organizations to manage corporate communications efficiently. Its ability to host multiple domains makes it suitable for sectors like warehouse distribution and retail, with installation options that enhance security and privacy. However, faster Outlook integration, improved MS Teams and CRM system integration, and AI functionalities are sought after by users. Some demand a cloud version, Linux support, and better documentation. Still, KerioConnect remains a reliable choice for those needing on-premise capabilities.

What are KerioConnect's Key Features?

Ease of Use: Simplified interface for seamless navigation.
Robust Security: Advanced protection measures to safeguard data.
Spam Filtering: Efficiently reduces unwanted emails.
Platform Compatibility: Integrates with Office, Apple, and ActiveSync.
Log Analysis: Offers detailed insights for server management.
Multiple Domain Support: Manages diverse domains with ease.

What Benefits Should Users Expect?

Cost Efficiency: Lowers operational costs compared to alternatives.
Resource Minimization: Requires minimal system resources.
Deployment Flexibility: Allows tailored on-premise installations.
Enhanced Security: Provides privacy through internal hosting options.
Reliable Support: Access to reseller services from Sophos.

KerioConnect is widely utilized in SMBs across sectors like retail and warehouse distribution for its capability to handle multiple domains and integrate with Outlook for communication management. Resellers offer it as a dependable on-site email management solution, letting businesses maintain oversight and security control.

GFI

Microsoft Defender for Office 365 offers real-time email security, enhancing threat detection through integration within the Microsoft ecosystem. Its user-friendly interface and central management streamline operations, providing robust protection against phishing, ransomware, and malware.

Defender for Office 365 is focused on efficiently securing email communication by safeguarding against phishing, malware, and spam threats. With its strong integration with other Microsoft services, it is tailored to improve endpoint security and identity protection. Its centralized management tools simplify threat prioritization, while the automated threat response capabilities ensure swift actions against potential risks. Organizations leverage its capabilities to efficiently manage their cybersecurity efforts, particularly in remote work environments, while maintaining a secure system across Office 365 applications and Azure-hosted services.

What are the key features?

Real-time Email Protection: Continuously monitors and protects email communications.
Safe Attachments and Links: Scans attachments and links for potential threats.
Anti-Phishing Measures: Provides tools to detect and block phishing attempts.
Integration with Microsoft Services: Seamlessly connects with other Microsoft applications for enhanced security.
Automated Threat Responses: Activates immediate responses to detected threats.

What benefits should users expect from reviews?

Time Savings: Automates processes to reduce manual threat management efforts.
Improved Cybersecurity: Strengthens organizational defenses against various cyber threats.
Efficient Remote Work: Enhances protection for remote teams and virtual collaborations.
Comprehensive Coverage: Extends protection across Office 365 and Azure services.

Implementations of Defender for Office 365 vary across industries, optimizing email security for sectors such as finance, healthcare, and education. In finance, it aids in protecting sensitive financial data from phishing and fraud. Healthcare benefits from secure communications, ensuring patient data privacy. Educational institutions use it to maintain secure virtual learning environments against cyber threats.

Microsoft

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.

Buyer's Guide

KerioConnect vs. Microsoft Defender for Office 365

August 2026

Free Report: KerioConnect vs. Microsoft Defender for Office 365

Find out what your peers are saying about KerioConnect vs. Microsoft Defender for Office 365 and other solutions. Updated: August 2026.

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