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Intelligent. Complete. MailGuard.

Email spam filter for companies with proactive phishing protection and malware defense. MailGuard blocks threats directly in the gateway before they reach the inbox.

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What MailGuard does

Attacks blocked before they land.

Multi-layered detection against the most common threats — click through.

Phishing and spear-phishing — caught in real time.

MailGuard analyses content, sender behaviour and link structure. Suspicious mails never reach the inbox — without false alarms in day-to-day work.

  • URL rewriting with reputation check at time of click
  • Detects brand impersonation: Microsoft, DHL, banks & more
  • Learns from your mail flow — few false positives
  • Reports show risk sources, trends and click rates
Phishing protectionSecure Microsoft 365

Attachments are unpacked, inspected and disarmed.

Suspicious Office documents and archives are unpacked recursively, checked for their true file type and stripped of macros and active content. Detects macro loaders and executables disguised as images.

  • True file type by signature, not just the extension
  • Protects from macro malware, loaders and active content in PDF and Office files
  • Quarantine with one-click release for IT admins
  • Hidden attachments in encrypted archives are detected
Email attachment protectionRansomware protection

Fake executive emails — automatically flagged.

Fraud detection catches when someone impersonates a manager or accounting, even from an external account that looks like an internal one.

  • Display-name spoofing flagged instantly
  • Lookalike domains (e.g. Cyrillic letters) filtered
  • Suspicious payment requests are held, not delivered
  • Optional awareness training: phishing simulations included
CEO fraudPhishing protection

Spam detection with a configurable threshold, without losing important mail.

Multi-layered filter with real-time reputation: rspamd rules, Spamhaus lists, fuzzy hashes and our own heuristics complement each other. Quarantine with self-service for end users.

  • Multi-layered: rspamd, Spamhaus reputation, fuzzy hashes, heuristics
  • Quarantine self-service with daily digest
  • Whitelist/blacklist per user, group or domain
  • Bypass for newsletters and transactional mail
Enterprise spam filterSecure Microsoft 365

Accidental data leaks — automatically prevented.

Detects sensitive content (IBAN, patient data, contracts) and blocks or encrypts before sending. Protects you from expensive GDPR incidents.

  • Detects structured data: IBAN, patient ID, credit card
  • Reacts by rule: block, encrypt, warn
  • OCR for images and PDFs — no leak via screenshot
  • Audit log for data protection officers and compliance
NIS2 email securityEmail attachment protection

Detection and filtering intelligence

MailGuard detects spam, phishing and malicious content early and combines phishing email protection with intelligent analysis directly in the email gateway.

Real time detection and defense

  • Real time detection
  • Threat protection
Real time analysis Threat detection

Analysis features

  • Multi stage content analysis with rules, reputation and fuzzy hashes.
  • Reputation checks via real time blacklists (RBL) and Geo IP.
  • Heuristic pattern recognition for early detection.
AI engineHeuristicsRBLIP

Protection features

  • Full validation of SPF, DKIM, DMARC, and ARC.
  • Hourly refreshed signatures and reputation data, hold instead of deliver when a scanner is down.
SPF DKIM DMARC ARC

Advanced link filtering

Deep inspection of URLs even when hidden in barcodes or QR codes.

  • URLs are detected and checked in attachments, barcodes, and QR codes.
  • Full sanitizing (rewrite) of suspicious links.
https://suspicious-link.com
Sanitized (safe)

Advanced analysis

Decomposition and inspection of nested files and archives for hidden threats.

  • Deep directory analysis detects hidden threats.
  • Macro detection and auto sanitizing for Office documents.

Spam filter management

  • Fuzzy detection Recognises known spam waves through fuzzy hashes.
  • Custom feedback Individual feedback for training and tuning.
  • Custom policies Manage your own rules and regex filters professionally.

Rules, Routing and Mail Security Gateway

Intelligent control for inbound and outbound email. Fully customizable for central policies, routing rules, and secure processes in the Mail Security Gateway.

Filter policies and configuration:

  • Custom rules per domain, user, or group
  • Control by score, sender, subject, content, attachment type, and more
  • Use predefined or custom rule sets

Actions and measures:

  • Forward or reject by rule
  • Subject changes or delivery modifications
  • Remove email headers and server topology
BLOCKED
DLP policy violation Confidential attachment detected. Outbound delivery blocked.
Optional add on module

Data loss prevention (DLP)

Prevent data exfiltration and protect sensitive information with intelligent filtering and content scanning.

  • Deep content inspection for subject, body, and attachments
  • Advanced link filtering including barcode and QR code parsing
  • Rule based blocking and quarantine of outbound emails

Threat Protection in Detail

Every threat deserves dedicated attention. Dive deep into each protection layer.

Phishing Protection

Automatically detect and block forged senders, manipulated links, and social engineering.

Discover phishing protection

CEO Fraud Protection

Stop executive impersonation, BEC, and fraudulent payment instructions in real time.

Discover CEO fraud protection

Ransomware Protection

Signature and heuristic scanning with macro analysis block ransomware before delivery.

Discover ransomware protection

Email Attachment Protection

Content Disarm & Reconstruction removes macros and malware from file attachments.

Discover CDR technology

Spam Filter

Multi-layered detection with intelligent quarantine and self-service digest.

Discover spam filter

Microsoft 365 Security

Complement Exchange Online Protection and elevate M365 security to enterprise level.

Discover M365 protection

Enterprise infrastructure and security

Certified protection, seamless integration, and full transparency.

Monitoring and audit logs

Live dashboardVisualized spam timeline and mail flow in real time.
End to end audit loggingAudit log and cryptography logging stored tamper proof.
RetentionStandard 90 days retention and export.
SIEM exportSecurity events via pull API to Splunk, Sentinel, QRadar and Elastic.
Mails processed
128.4k
Encrypted
Spam trend

Integration and compatibility

Seamless integration into your existing system landscape.

Compatibility & Clients
Native support for Microsoft Outlook, Apple Mail, iOS, Android, and all common email clients — without additional installations.
OUTLOOKAPPLE MAILMOBILE
Integration & Management
Scheduled sync with Microsoft Entra ID, with a local Active Directory through an outbound agent and with LDAP. Central control from the interface.
ENTRA IDAD/LDAPSAML SSO
Team members
Manage members of your team.
Invite
Search members
NameEmailRoleJoined
M
Maximilian M.
m.mueller@example.com
Owner
P
3.4.2025
S
Sarah K.
s.krause@firm.com
Owner
20.5.2025
T
Timo S.
t.schmidt@mail.de
Contact
2.9.2025

Infrastructure, Performance & Deployment

Highly available architecture for maximum reliability.

Infrastructure and architecture

  • ISO 27001 hostingGeo redundant servers in Germany (the EU and Berlin).
  • Active active clusterFor maximum resilience and load distribution.
the EUBerlin ISO 27001

Performance and reliability

  • SLA guarantee99.9% guaranteed system availability.
  • High performance routingMinimal latency (< 50ms) for email processing.
SLA guarantee
99.9%
Avg. latency
< 50ms

Deployment & Multi-Tenancy

  • ISO 27001 certified hostingHosting in ISO 27001 certified EU data centers (Germany)
  • Flexible service packagesCustom service packages per tenant
CLOUD / SAAS
ON-PREM

Support and documentation

Benefit from a broad range of support services

24/7 ticketing

Guaranteed response times around the clock

Phone support

Personal contact through prioritized phone support

Documentation and FAQs

Comprehensive documentation, step by steps, and FAQs

Intelligent email spamfilter for businesses

Many attacks are detected too late. As an email spam filter for companies, Conbool MailGuard detects spam, phishing and malware directly in the gateway before risks arise in the inbox.

Recommended

With MailGuard

  • Proactive Threat Detection
    Threats are identified and neutralized before reaching the inbox.
  • Rule-based filtering with reputation data
    Signatures, reputation lists and fuzzy hashes are refreshed hourly, and every decision is explainable.
  • Traceable decisions
    Every filtering decision is traceable in message tracking, every admin action in the event log.
  • Scales With Your Team
    Protects 10 or 10,000 mailboxes with zero extra overhead.
NIS2-compliant email security
MailGuard covers section 30 (2) no. 2 BSIG: incident management and threat detection.
NIS2 compliance in detail

Frequently Asked Questions about Conbool MailGuard

Why is the standard spam filter of Microsoft 365 or Exchange not sufficient?
Conbool MailGuard closes critical security gaps of standard filters, especially with targeted phishing campaigns, CEO fraud, and zero-day malware. Through cloud attachment inspection with CDR, modern heuristics, and multi-stage analysis, we intercept threats before they reach the Microsoft ecosystem and thus the inbox.
How does MailGuard protect against retroactively manipulated links and attachments?
Incoming URLs are rewritten and checked against reputation and malware feeds at the time of click, including Spamhaus DBL, zero-reputation domains and PhishTank. This also blocks links redirected to a malicious site after delivery. File attachments are unpacked, checked for their true file type and stripped of macros and active content before delivery.
Can the platform stop unintentional data loss (DLP)?
Yes, integrated Data Loss Prevention (DLP) filters automatically analyze outgoing messages for sensitive information such as credit card data, IBANs, or defined company secrets. These emails can be centrally blocked, forwarded to compliance officers, or – in conjunction with SecureMail – automatically encrypted.
How does our IT department maintain control over false positives?
MailGuard offers a multi-tenant governance console with detailed live message tracking. Administrators can granularly set quarantine policies, while end users can safely release harmless emails themselves through regular quarantine reports (digests), which relieves the IT helpdesk.
Does the deep email inspection slow down our communication?
No, the entire engine of Conbool is designed for highest enterprise performance. The complex analyses take place in the millisecond range, so the email flow for business operations remains virtually delay-free.
Can security policies be adapted for different departments?
The ruleset can be segmented very precisely. For example, you can define more restrictive filters and stricter CDR rules for management or the finance department than for general newsletter or info mailboxes.

Ready to secure your company? Let's talk.?

Protect your infrastructure with phishing protection, malware defense, and central security policies.

MailGuard blocks threats before they reach the inbox and strengthens your email security in real time.

No credit card required - 30 days free - Cancel anytime

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Spam filter for businessesDiscover phishing protectionStrengthen M365 securityPhishing simulation for your teamDMARC authenticationDANE and TLSASet up MTA-STSAnalyze TLS-RPTDirectory harvesting protection