Question
If I use SendGuard, do my emails flow through SendGuard servers? Is mail flow affected in any way?
Answer
SendGuard works as an add-on within your Microsoft 365/Outlook environment and operates before an email is sent. Its role is to help prevent human errors — such as sending to the wrong recipient, attaching the wrong file, or accidental Reply-All incidents — before the message leaves the user’s mailbox.
How SendGuard Works
By default, SendGuard performs its checks locally on the user’s computer before the email is sent.
- Email messages continue through your existing Microsoft 365 / Exchange Online mail flow
- No email rerouting or mail relay changes are required
- No MX record changes are needed
- SendGuard does not sit in the middle of your email delivery path
- Existing email security, compliance, and transport configurations remain unchanged
For standard protection features, processing happens locally and your email delivery path remains untouched.
Premium Attachment Scanning
If you are using SendGuard Premium with attachment content scanning enabled, attachment content may be checked by SendGuard services as part of the pre-send protection process. This scanning helps identify risks before an email is sent.
However:
- This does not change your email routing
- Emails are not relayed through SendGuard servers
- Your existing Microsoft 365 / Exchange Online mail flow remains unchanged
- No mail flow, MX, or transport rule redesign is required
- SendGuard still does not become part of the email delivery path
What SendGuard Does Instead
Before an email is sent, SendGuard can:
- Display confirmation prompts
- Apply policy and compliance checks
- Warn users about risky recipients or content
- Help prevent accidental Reply-All scenarios
- Provide send delay / undo-send protection
Why This Matters
Because mail flow remains unchanged:
- Deployment is quick and low-friction
- Existing Microsoft 365 protections continue to work normally
- There is no impact on email delivery performance
- IT teams do not need to redesign their email infrastructure
In short: SendGuard adds a before-send prevention layer that complements Microsoft 365 without changing how email is delivered. By default, checks occur locally on the user’s device, and even when premium attachment scanning is enabled, SendGuard does not alter your mail routing.