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Kaspersky Security for Mail Server vs Microsoft Defender for Office 365 comparison

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Comparison Buyer's Guide

Executive SummaryUpdated on Nov 8, 2026

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

Kaspersky Security for Mail...
Ranking in Email Security
29th
Ranking in Secure Email Gateway (SEG)
10th
Average Rating
7.6
Reviews Sentiment
6.8
Number of Reviews
8
Ranking in other categories
No ranking in other categories
Microsoft Defender for Offi...
Ranking in Email Security
2nd
Ranking in Secure Email Gateway (SEG)
2nd
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
61
Ranking in other categories
Email Archiving (2nd), Advanced Threat Protection (ATP) (3rd), Microsoft Security Suite (8th)
 

Mindshare comparison

As of November 2026, in the Email Security category, the mindshare of Kaspersky Security for Mail Server is 0.9%, up from 0.6% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 5.0%, down from 10.6% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 3655.0%
Kaspersky Security for Mail Server0.9%
Other94.1%
Email Security
 

Featured Reviews

ZS
Systems Specialist/ Administrator at ALFA International Company Limited.
User interface updates needed but achieves cost savings and threat protection
We are using Kaspersky Security for Mail Server to enhance our email system’s security and protect against threats Kaspersky Security for Mail Server handles spam and phishing attempts well. I have not experienced any spam issues. Its malware detection effectively manages the security of our…
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 feature is the straightforward setup."
"Kaspersky Security for Mail Server provides protection against email spams and blacklisted emails which are suspicious, making it a good product."
"The most valuable feature of the solution stems from the fact that it is a highly reliable and dependable solution."
"With both of them working together, we have the perfect solution for mail."
"I find the product valuable because it provides easy integration with other platforms like Fortinet firewalls."
"You can install the plugins on the same machine hosting your exchange solution. It's a good complement for Sophos security, which scans the traffic before it reaches your mail service. Kaspersky is on the mail server itself while Sophos handles the incoming traffic. With both of them working together, we have the perfect solution for mail."
"The integration rate is very high in Kaspersky, which is why most of our customers like it."
"The most valuable features are the anti-phishing and anti-spam capabilities."
"It definitely is a must for email protection and O365 app DLP, and combined with Microsoft Defender for Endpoint, Microsoft Defender for Identity, and MCAS, it provides a holistic solution for threat protection, email protection, O365 apps protection, and DLP for both internal and external risks."
"The most valuable feature is protection against malicious links, fishing, and impersonation. You can train people to be aware of these threats, but they're not always careful. When they're using their phones between meetings, they click on a link, and it's game over."
"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."
"Defender helps us prioritize threats across our organization."
"The feature of Microsoft Defender for Office 365 that I like the most is probably the email features specifically, because those are the ones that a typical end user will accidentally click on a link not knowing what it is, and it'll catch it, and then it'll feed it over to Defender and stop the attack from happening before it actually can."
"The feature I like the most about Microsoft Defender for Office 365 is that it typically runs in the background—you do not know it is there until you need to access it."
"The features I appreciate most about Microsoft Defender for Office 365 are admin notifications for potential threats along with protecting our Microsoft apps such as Outlook from potential phishing attacks."
"The deployment capability is a great feature."
 

Cons

"I rated the overall solution a five out of ten. If a user is looking for a low-budget solution with mid-level security without AI features, Kaspersky Security for Mail Server is suitable."
"The stability of Kaspersky Security for Mail Server is okay, not so much of an issue."
"Kaspersky lacks in the area of customization, so simpler customization options need to be provided to users."
"The solution is not 100 percent stable and that can use improvement."
"It would be great if Kaspersky could do what Sophos does for us. However, we love having these two different technologies doing the same thing. Sometimes Sophos has the patch to block a novel threat, but Kaspersky doesn't."
"The biggest problem in the solution is related to its license renewal since it is pretty hard in Kaspersky to find out the procedure to renew a license."
"I have only made contact via email, and it is a little slow. I would give customer service a rating of six or seven. Improving Spanish support would greatly benefit users."
"Sometimes Sophos has the patch to block a novel threat, but Kaspersky doesn't."
"The pre-sales cost calculations could be more transparent."
"Microsoft Defender for Office 365's Mac functionality requires improvement to deliver the same level of protection found on Windows devices."
"Microsoft needs to broaden its global support presence by establishing teams of subject-matter experts in all regions."
"Microsoft Defender for Office 365 could improve by giving customers information on techniques to prevent threats."
"The visibility for the weaknesses in the system and unauthorized access can be improved."
"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."
"The changes to customer service, specifically the new model for support agreements, are not favorable."
"Microsoft Defender for Office 365 must improve the overall management style, including the GUI. It also needs to change the filters so that it is easy to whitelist and blacklist data."
 

Pricing and Cost Advice

"The solution is not expensive."
"My company makes annual payments towards the licensing costs solution."
"Price-wise, I would rate this product a four out of five. It could be a bit cheaper."
"The solution offers one of the best prices possible to its users, making it even better than Barracuda. Kaspersky Security for Mail Server is ten times cheaper than Barracuda."
"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
"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."
"The pricing is normal. Considering its popularity, it's not overpriced."
"The product is very expensive."
"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's a user-base subscription."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"The license is expensive because the cost is based on the number of users."
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Top Industries

By visitors reading reviews
Construction Company
11%
Educational Organization
9%
Comms Service Provider
9%
Outsourcing Company
8%
Computer Software Company
11%
Manufacturing Company
10%
Financial Services Firm
8%
Comms Service Provider
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business6
Large Enterprise3
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise11
Large Enterprise32
 

Questions from the Community

What is your experience regarding pricing and costs for Kaspersky Security for Mail Server?
The pricing is moderate. It is not expensive but not cheap either. For Mexico, a good price is about 20 dollars per agent.
What needs improvement with Kaspersky Security for Mail Server?
Regarding Kaspersky Security for Mail Server, I have not compared with other solutions, but I will compare and provide feedback. It is a reliable and fast security solution, and I can say it blocks...
What is your primary use case for Kaspersky Security for Mail Server?
I work on a mail protection service, specifically Kaspersky Security for Mail Server. I work with Kaspersky Security for Mail Server.
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...
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...
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.
 

Also Known As

No data available
MS Defender for Office 365
 

Overview

 

Sample Customers

Vimpel Com, Estrella Galicia, Krombacher
Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Find out what your peers are saying about Kaspersky Security for Mail Server vs. Microsoft Defender for Office 365 and other solutions. Updated: October 2026.
921,028 professionals have used our research since 2012.