Most organizations understand that email backup means not losing inbound messages. Fewer have thought through what happens to their operations during an email outage — the hours their teams cannot respond to customers, cannot coordinate internally, cannot send time-sensitive documents. Email continuity addresses that operational gap. It is not only about preserving mail. It is about keeping people working.
What Email Continuity Is
Email continuity is a service that gives your users a live, accessible emergency mailbox whenever your primary mail system is unavailable. When the primary goes down — whether for minutes or days — users sign in to a browser-based portal and continue sending and receiving email. New inbound messages appear in the emergency mailbox as they arrive, and outbound messages are delivered to recipients through the continuity platform's own mail infrastructure.
When the primary system recovers, the mail received during the outage is delivered back to the primary mailboxes automatically, so nothing that arrived during the outage is lost.
Continuity Options for Any Mail Platform
Infinity Data Center's continuity services are available for any business mail environment — not just StrataMail. Whether your organization runs StrataMail, on-premise Exchange, Microsoft 365, Google Workspace, or another hosted email platform, continuity can be layered in as a protection service that operates independently of your primary mail system. There is more than one way to do it, and the options are not interchangeable:
- StrataMail Email Continuity — a shadow mailbox and branded webmail for users, plus a relay queue that holds inbound mail for up to 30 days and delivers it when the primary recovers. Works behind SpamWeeder Premium, Proofpoint, Mimecast, Barracuda, or Microsoft Defender.
- StrataMail Continuity IMAP — for providers whose users need Outlook and phone mail apps to keep working through an outage, with 7, 30, 60, or 90 days of history. Offered to resellers; contact us for pricing.
- Filter-based continuity — Proofpoint Essentials includes a 30-day emergency inbox, and VIPRE Email Cloud includes 90 days of continuity. Users work through the filter's web portal; Outlook and phone apps do not keep working.
- StrataMX Backup — queue protection only. Mail is held and redelivered, but users have no access during the outage.
Microsoft 365 Email Continuity
Microsoft 365 is a reliable platform, but it is not immune to outages. Microsoft's service health history shows periodic incidents affecting Exchange Online — including authentication failures, message delivery delays, and service unavailability in specific regions. For organizations whose entire email infrastructure lives in Microsoft's cloud, these events can mean complete loss of email access with no fallback.
StrataMail Email Continuity provides an independent continuity layer for Microsoft 365 customers — so when Microsoft has an incident, your team is not simply waiting for Microsoft to resolve it. It also covers the DNS propagation window of a Microsoft 365 tenant-to-tenant migration. Contact us to discuss Microsoft 365 continuity configuration.
Continuity in Disaster Recovery Planning
Email continuity is often missing from formal disaster recovery plans — or included as an afterthought. This is a mistake. When a disaster takes down primary infrastructure, email is the first communication tool an incident response team needs. If email is part of the infrastructure that failed, response coordination degrades immediately.
A properly configured continuity service takes over automatically: your filter routes mail to the continuity platform as soon as your primary stops answering, and outage alerts go out to the people you choose. By the time your team is aware of the incident and beginning response, inbound mail is already landing in the emergency mailbox. This is particularly important for scenarios where IT staff themselves may not be immediately reachable.
Infinity Data Center's continuity infrastructure is hosted in our Knoxville data center — geographically independent from most customer on-premise environments, providing meaningful separation from common regional risk events.
RTO and RPO for Email
Two metrics define email availability requirements in a DR plan. Recovery Time Objective (RTO) is how quickly email access must be restored after an outage begins. For most businesses, an email RTO measured in minutes rather than hours is appropriate. Email continuity meets this target because failover happens automatically when the primary server stops answering, not when someone notices.
Recovery Point Objective (RPO) is how much mail you can afford to lose. With StrataMail Email Continuity, the answer for inbound mail is none: every message received from the moment failover begins is kept in the continuity mailbox and in the relay queue, retained for up to 30 days, and delivered to the primary system on recovery. Mail history from before the outage stays in the primary system.
Testing Your Email Continuity
A continuity service that has never been tested is infrastructure you cannot rely on in a real event. Basic continuity testing should be performed at least annually and should include:
- Access the continuity portal from outside your office network — from a mobile device or home connection — to verify it is reachable independently of your primary infrastructure
- Sign in and confirm the mailbox portal loads correctly
- Send a test message from the continuity portal and confirm it is delivered to the recipient
- Receive a test message sent to your address during the test and confirm it appears in the emergency mailbox
- Verify the portal URL and sign-in procedure are documented in your DR runbooks and accessible to key staff when primary systems are unavailable
See the continuity comparison at Infinity Data Center to see the options side by side. Contact us or call 866.790.4678 to discuss email continuity options for your environment.