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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 Dec 3, 2024

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

Cloudflare One
Sponsored
Ranking in Email Security
20th
Average Rating
8.6
Reviews Sentiment
6.5
Number of Reviews
23
Ranking in other categories
Secure Web Gateways (SWG) (13th), Data Loss Prevention (DLP) (20th), Cloud Access Security Brokers (CASB) (12th), Distributed Denial-of-Service (DDoS) Protection (7th), Software Defined WAN (SD-WAN) Solutions (12th), Access Management (11th), Bot Management (3rd), ZTNA as a Service (9th), ZTNA (4th), Secure Access Service Edge (SASE) (10th), Remote Browser Isolation (RBI) (3rd)
Kaspersky Security for Mail...
Ranking in Email Security
28th
Average Rating
7.6
Reviews Sentiment
6.8
Number of Reviews
8
Ranking in other categories
Secure Email Gateway (SEG) (11th)
Microsoft Defender for Offi...
Ranking in Email Security
2nd
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
61
Ranking in other categories
Email Archiving (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (8th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of May 2026, in the Email Security category, the mindshare of Cloudflare One is 1.7%, up from 1.6% compared to the previous year. The mindshare of Kaspersky Security for Mail Server is 0.8%, down from 0.9% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 6.9%, down from 12.9% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 3656.9%
Cloudflare One1.7%
Kaspersky Security for Mail Server0.8%
Other90.6%
Email Security
 

Featured Reviews

CV
Network Architect at IP Dimension
Cloud security has improved remote access and has reduced costs for smaller client sites
I have used Cloudflare One's Identity-Aware Proxy, and it is quite straightforward from what I have seen so far. The app registration on the Azure side integrates fully into Cloudflare, and I am very satisfied with that part because it is easy to set up. The integration of Cloudflare One's Secure Web Gateway and Zero Trust Network Access works without any issues. That part is pretty automatic, and if you complete the rest of the setup, it comes together by itself with no issues from my side. What makes it nice is that we can actually start replacing on-site firewalls at this stage for the smaller clients because it does not matter if they go to a coffee shop or work from home; they are still secured by the same connection. The hops get shorter and you get better latency. We have done testing to see if it is better. One thing that we did notice with our proof of concept with our current client is that they have people connecting from the UK. When they used their previous VPN solution, uploading CAD drawings and other files to the server took a long time. They mentioned that it is much quicker on Cloudflare One's solution. I definitely believe that is part of the improved performance, and I am satisfied with that as well. What is nice about Cloudflare One is that it makes the setup easier and also easier to train technicians to maintain it. Compared to legacy systems, we do not need to get fancy firewalls in place that are costly. That is definitely also a cost-saver with Cloudflare One.
KamranBhatti - PeerSpot reviewer
Network Engineer at a computer software company with 11-50 employees
Provides reliable real-time email protection and offers competitive pricing features
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 better than other competitor software. Kaspersky Security for Mail Server has support for Windows and Linux, but regarding improvement, I have to dig deep and will have to do research on that. I have not checked into much detail about what can be better in Kaspersky Security for Mail Server. I have checked in general. If given some time, I can check and compare with other solutions. Regarding Kaspersky Security for Mail Server, I have found this is quite a good solution. It has a good response and good detection capability. I have not checked other products, so I cannot give any detailed or specific feedback regarding that. From what I have checked from Kaspersky mail security, it is satisfactory.
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

"Enables me to work from two locations."
"Cloudflare Zero Trust Platform removes the risk of exposing the applications to the public."
"It's a perfect solution from my perspective; it's easy to understand and easy to configure."
"The solution has different options that can be used to differentiate DDoS attacks."
"The simplicity of the solution is its valuable features as almost no effort was needed to learn the configurations. It is also one of the cheapest firewalls available in this category."
"Cloudflare Access is a stable solution."
"What makes it nice is that we can actually start replacing on-site firewalls at this stage for the smaller clients because it does not matter if they go to a coffee shop or work from home; they are still secured by the same connection."
"Using Cloudflare One makes my work quite easy because for DDoS protection, all I need to do is understand the OSI model and click; it makes it easier than trying to write a command line or use a Linux command."
"We have achieved cost savings of up to thirty percent by using Kaspersky Security for Mail Server."
"I find the product valuable because it provides easy integration with other platforms like Fortinet firewalls."
"The most valuable feature of the solution stems from the fact that it is a highly reliable and dependable solution."
"The primary use case of this solution is to filter emails and only allow the legitimate ones through."
"Kaspersky Security for Mail Server provides protection against email spams and blacklisted emails which are suspicious, making it a good product."
"The most valuable features are the anti-phishing and anti-spam capabilities."
"With both of them working together, we have the perfect solution for mail."
"The most valuable features are the anti-phishing and anti-spam capabilities."
"Overall, I would rate Microsoft Defender for Office 365 at a ten."
"The insights provided with Microsoft Defender for Office 365 are helpful because it comes with the E5 license, and by default, we can use a lot of capabilities."
"Does a thorough job of examining email and URLs for malicious content."
"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."
"The product is not resource-intensive."
"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."
"Some of the valuable features on the email side are anti-phishing, anti-malware, and Safe Links."
"The most valuable feature is the integration; it's a single console, so we don't have to switch around between multiple products, and another valuable feature is the ease of operations and maintenance."
 

Cons

"The response time for support must be reduced."
"The initial onboarding was causing us some confusion."
"Cloudflare DDoS has poor technical support."
"Our subscription plan for the solution has a limitation of bot signatures."
"Cloudflare Zero Trust Platform needs to improve its documentation. It took time to do the implementation."
"The initial onboarding was causing us some confusion."
"Our customers no longer use Cloudflare because its service is subpar."
"When there are any dynamic changes in complex applications, the tool takes a lot of time, making its analytics-related area a major matter of concern where improvements are needed."
"Encrypted email attachments are not being monitored by this solution, which is an area that they need to work on."
"Sometimes Sophos has the patch to block a novel threat, but Kaspersky doesn't."
"Kaspersky lacks in the area of customization, so simpler customization options need to be provided to users."
"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 solution is not 100 percent stable and that can use improvement."
"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."
"Encrypted email attachments are not being monitored by this solution, which is an area that they need to work on."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"If I could improve anything, I would reduce the cost."
"The pre-sales cost calculations could be more transparent."
"It is not up to the mark in comparison with Wiz or Palo Alto."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"Microsoft Defender for Office 365 should be more proactive."
"Microsoft sometimes has downtime, and we'll get several incidents coming in back to back. We have a huge backlog of notifications, many of which may be false positives. However, there might be serious alerts, so we can't risk dismissing all of them at once."
"Sometimes, phishing emails manage to pass through the filter, so the system needs to enhance its phishing email detection capabilities."
 

Pricing and Cost Advice

"The solution's pricing lacks transparency."
"The price tag is no longer $200,000, but rather $300,000 to $400,000. It's twice."
"The prices are slightly expensive."
"The solution is not that expensive."
"The pricing of the solution is cheap. The licensing cost is also very low. I rate the cost and pricing a three out of ten."
"My company has to make yearly payments towards the licensing costs attached to the solution. There are no hidden charges apart from the licensing costs of the solution."
"Cloudflare Zero Trust Platform's pricing is good."
"The pricing is somewhere in the middle. I would rate the pricing a seven out of ten."
"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."
"My company makes annual payments towards the licensing costs solution."
"The solution is not expensive."
"Price-wise, I would rate this product a four out of five. It could be a bit cheaper."
"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."
"The pricing is normal. Considering its popularity, it's not overpriced."
"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."
"The product is expensive."
"The pricing has become expensive."
"I know that the product is incredibly expensive."
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893,311 professionals have used our research since 2012.
 

Top Industries

By visitors reading reviews
Construction Company
20%
Comms Service Provider
11%
Financial Services Firm
8%
Manufacturing Company
6%
Retailer
11%
Computer Software Company
9%
Construction Company
8%
Manufacturing Company
8%
Computer Software Company
12%
Financial Services Firm
9%
Manufacturing Company
8%
Comms Service Provider
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business10
Midsize Enterprise1
Large Enterprise12
By reviewers
Company SizeCount
Small Business6
Large Enterprise3
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise11
Large Enterprise32
 

Questions from the Community

What needs improvement with Cloudflare Access?
Cloudflare Access has strong integration with Microsoft, among other platforms. However, when it comes to Kaspersky, ...
What is your primary use case for Cloudflare Access?
Cloudflare Access provides secure access to internal applications for employees, external members of the organization...
What advice do you have for others considering Cloudflare Access?
Cloudflare Access is one of the best integrations available. While about two hundred vendors offer similar services, ...
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 a...
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 provid...
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 ...
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...
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 ...
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

Cloudflare Area 1 Email Security, Cloudflare Bot Management, Cloudflare Gateway, Cloudflare Zero Trust Platform, Cloudflare DDoS, Cloudflare SASE & SSE Platform
No data available
MS Defender for Office 365
 

Overview

 

Sample Customers

23andMe
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: April 2026.
893,311 professionals have used our research since 2012.