Mail Routing for Microsoft 365
Cross-Tenant Migration
Complete your cross-tenant migration and transfer your domain names between your Microsoft 365 tenants without downtimes.
What is Mail Routing?
After a cutover mail migration between Microsoft 365 tenants, moving domain names can take up to 48 hours. To avoid non-delivery reports for any emails sent to those domains, Cloudiway's platform ensures all incoming mail is routed to the intended user regardless of the status of the domain.
Detach your SMTP domain from the source tenant and reattach it to the target tenant without downtime. Mails are routed to the correct target mailboxes with zero downtime during the manipulation.
How Mail Routing Works
Simple process for zero-downtime domain transfer
Configure MX Records
Point your domain MX records to Cloudiway mail routing servers before detaching from source tenant.
Detach Domain
Remove the SMTP domain from the source Microsoft 365 tenant. During this time, Cloudiway captures all incoming mail.
Attach to Target
Add and verify the domain on the target Microsoft 365 tenant. This typically takes a few hours.
Update MX Records
Point MX records back to Microsoft 365. All queued emails are delivered and normal mail flow resumes.
When to Use Mail Routing
Seamless domain transfer for enterprise migrations
Cross-Tenant Migration
After a cutover mail migration between Microsoft 365 tenants, moving domain names can take up to 48 hours. Mail Routing ensures all incoming mail reaches the intended user.
Domain Transfer
Detach your SMTP domain from the source tenant and reattach it to the target tenant without downtime. Mails are routed to the correct target mailboxes.
Avoid NDR
Prevent non-delivery reports during the domain transition period. All emails are captured and forwarded to the correct recipient.
M&A Consolidation
During mergers and acquisitions, consolidate email domains from multiple tenants into a single unified Microsoft 365 environment.
Mail Routing Features
Enterprise-grade mail routing for Microsoft 365 migrations
Zero Downtime
Transfer your domain names between Microsoft 365 tenants without any service interruption. Emails continue flowing seamlessly during the entire process.
Automatic Mail Routing
Incoming emails are automatically rewritten and routed to the correct target mailbox, regardless of domain status during migration.
Nothing to Install
100% cloud-based SaaS solution. No software or agents to install on any server or workstation.
Transparent Migration
End users experience no disruption. Emails arrive in the correct mailbox without any manual intervention required.
All-in-One Solution
Part of the complete Cloudiway tenant-to-tenant migration suite including mailbox migration, GALSync, and FreeBusy coexistence.
Enterprise Postfix
Built on Postfix, the industry-standard mail transfer agent trusted by organizations worldwide for reliable mail routing.
Mail Routing Benefits
Why organizations choose Cloudiway Mail Routing
Zero Downtime
Complete your domain transfer without any email service interruption.
Nothing to Install
Fully cloud-based solution with no software requirements.
Transparent Migration
Users experience seamless email delivery throughout the process.
Mail Routing FAQ
Everything you need to know about Mail Routing
What is the Mail Routing Service?
MailRouting is a cloud service that you can use during a Microsoft 365 cross-tenant migration. It rewrites incoming emails and routes them automatically to the target tenant while you transfer your domain.
How does the Mail Routing Service work?
You point your MX records to Cloudiway servers before detaching your domain. While the domain is being transferred, Cloudiway captures all incoming mail and forwards it to the correct target mailboxes. Once the domain is attached to the target tenant, you update MX records back to Microsoft 365.
When should I use Mail Routing?
You should use the Mail Routing service during your Microsoft 365 cross-tenant migration for transferring your domain name from the source tenant to the target tenant without email downtime.
How long can I use Mail Routing?
Mail Routing is designed for short-term use, typically up to 48 hours during domain transfer. For longer-term mail forwarding during extended migrations, you should use the Forwarders functionality instead.
How secure is the Mail Routing platform?
Mail Routing is built on Postfix, a widely trusted mail transfer agent used across the internet. The platform uses encrypted connections and follows industry security best practices.
What is the difference between forwarders and Mail Routing?
Mail Routing is for short-term use (up to 48 hours) during domain transfer. Forwarders are for long-term mail forwarding during extended migrations that may take weeks or months. Both ensure mail delivery but serve different migration phases.
Can I use Mail Routing with GALSync and FreeBusy?
Yes. Mail Routing is part of Cloudiway's complete enterprise coexistence suite. You can combine it with GALSync for address book synchronization and FreeBusy for calendar availability sharing during your migration.
What happens if the domain transfer takes longer than expected?
Cloudiway queues all incoming emails until the domain is successfully attached to the target tenant. Once configured, all queued emails are delivered to the correct mailboxes automatically.
Mail Routing Resources
Explore documentation, guides, and related solutions
Ready to migrate your domain?
Transfer your Microsoft 365 domain with zero email downtime