Mimecast Email Verification
Mimecast is an email security gateway that sits in front of corporate mail servers. Domains protected by Mimecast route mail through Mimecast MX records before delivery.
How Mimecast Handles Verification
Mimecast is a security gateway, not a mailbox host. Whether unknown recipients are rejected depends on each customer's recipient-verification configuration. Many tenants accept at the gateway and filter later, and Mimecast applies aggressive greylisting to unknown senders.
What Mailthentic does
We detect the Mimecast MX cluster, throttle by that cluster, and apply greylisting retries. When the gateway does not reject unknown recipients, we return an ambiguous, confidence-scored status rather than a false positive.
Quick Facts
MX Pattern
*.mimecast.com
Catch-All Behavior
Accepts all addresses
Typical SMTP Response
Varies, greylisting common, recipient verification depends on config
Provider Type
business
Common Domains
varies (any business domain behind Mimecast)
Best Practices for Mimecast
- Expect greylisting. First attempts are often deferred, retries are essential.
- Treat a gateway accept with caution. It may not confirm the underlying mailbox.
- Throttle by MX cluster. Many domains share Mimecast infrastructure.
Other Email Providers
Verify Mimecast email addresses
Our 9-point verification engine handles Mimecast's specific behavior automatically. Start free.