737-304-6185AD, VPNs, and Firewalls: The Hybrid Triangle Behind Most Outages
If you want to understand why hybrid environments fail, stop looking at individual systems.
Instead, look at the triangle where most failures occur:
- Identity (Active Directory / Entra ID)
- Connectivity (VPNs)
- Control (Firewalls)
Each of these is usually managed by a different team — or inherited from different eras of the organisation.
The gaps between them are where outages hide.
Active Directory: The Quiet Single Point of Failure
In hybrid setups, AD is no longer “just internal”.
It now underpins:
- Cloud authentication
- Conditional access
- SaaS application access
- Device trust
Yet many environments still treat it as:
- Stable
- Untouchable
- “Working fine”
Problems arise when:
- AD cleanup breaks cloud dependencies
- Sync rules evolve without visibility
- Legacy GPOs affect modern auth flows
Identity failures often look like “cloud issues” — but originate on-prem.
VPNs: Built for Yesterday’s Traffic Patterns
Many VPNs were designed for:
- Occasional remote access
- Admin connections
- Low-latency internal apps
They were not designed for:
- Always-on cloud traffic
- SaaS-heavy workflows
- Identity traffic flowing constantly
Symptoms include:
- Slow apps
- Random auth failures
- Location-specific issues
Because VPNs “mostly work”, they’re rarely reviewed — until they fail under load.
Firewalls: The Archaeological Record of Past Decisions
Firewalls in hybrid environments often contain:
- Rules added during incidents
- Temporary exceptions that became permanent
- Policies no one dares to remove
No one is confident what can be deleted.
The result?
- Over-permissive rules
- Shadow dependencies
- High blast radius when changes occur
The Failure Mode: When the Triangle Breaks
Most hybrid outages aren’t caused by one component failing.
They’re caused by misalignment:
- Identity expects a network path that no longer exists
- VPNs throttle traffic identity depends on
- Firewalls block “unexpected” cloud flows
Each component is technically “up”.
The service is down.
Why Ownership Gaps Make It Worse
Ask three teams who owns hybrid identity flow and you’ll get three answers.
Hybrid infrastructure spans:
- Identity teams
- Network teams
Without shared visibility, risk accumulates silently.
What Resilient Hybrid Setups Do Differently
Resilient teams:
- Map identity and network flows end-to-end
- Document assumptions explicitly
- Review legacy dependencies regularly
- Treat hybrid as a system — not components
They don’t remove everything.
They understand it.
Where to Start
You don’t need a redesign.
You need answers to:
- Which identity flows are critical?
- Which VPN paths they rely on?
- Which firewall rules protect them?
That’s exactly what the Hybrid Cloud Risk Map highlights.