VNet Peering
Private backbone connectivity between virtual networks, including regional and global peering and the transitivity limits.
Readiness
0%
1h 50m baseline
Exam memorization points
- Peering is a direct, one-to-one link between two virtual networks and requires non-overlapping address space.
- VNet peering is regional; global VNet peering connects networks in different regions.
- Peering is non-transitive. If A is peered to B and B to C, A cannot reach C without a network virtual appliance, Azure Firewall or a gateway.
- Peering configuration has two directions, and each side has its own status. Both sides must be created for the link to work.
- Gateway transit lets a spoke use the hub's VPN or ExpressRoute gateway: allow gateway transit on the hub, use remote gateways on the spoke.
- Traffic flows over the Microsoft backbone, and charges apply for ingress and egress on each side.
Traps & distractors
- Assuming transitive routing. Non-transitivity is the single most tested peering property.
- Creating only one direction of the peering and expecting connectivity.
- Trying to peer networks with overlapping address space - the creation is rejected.
- Combining service endpoints and peering incorrectly: a service endpoint on one VNet cannot be consumed from a peered VNet.
- Forgetting that gateway transit must be allowed on the hub and requested on the spoke, and that only one gateway is used.
Suggested lab
Prove peering is not transitive
Build a three-VNet chain and observe the break.
- 1Create three VNets in different regions with non-overlapping address space and one VM in each.
- 2Peer A to B in both directions and verify ICMP connectivity with Network Watcher connection troubleshoot.
- 3Peer B to C in both directions and verify B reaches C.
- 4Test A to C to observe that it fails.
- 5Add a 0.0.0.0/0 UDR on A to B's appliance (or Azure Firewall) and re-test to restore connectivity.
Microsoft Learn
- Virtual network peering overviewdoc
- Search Microsoft Learn: virtual network peering gateway transit non-transitive global peeringsearch
Live Microsoft Learn ingestion is a Sprint 2 item; until then links are curated and the search fallback always resolves.
Status
No time invested yet. Baseline assumptions only.
Self-assessed mastery
0%
High priority
Strong exam value. Schedule this week.
- Exam importance100% × 30% = 30.0
Learner-agnostic frequency on the real exam (5/5).
- Blueprint weight78% × 25% = 19.4
This topic's domain carries 17.5% of the exam objectives.
- Dependency leverage0% × 20% = 0.0
Nothing else in the graph depends on this topic.
- Current gap100% × 25% = 25.0
Readiness is 0%, so 100% of the topic is still uncovered.
Exam Priority Score = 30% importance + 25% blueprint + 20% dependency + 25% gap. Importance is exam frequency, blueprint is the domain's official exam weight, dependency is how many later topics this one unlocks, and gap is how far you currently are from ready.
Unlocks next
Leaf topic - nothing depends on it.
Baseline study time
1h 50m
Complexity
3 / 5
Remaining to target
1h 34m
Status weight
0%
Topics: peering, global peering, transitive, gateway transit, hub and spoke
Weak neighbours in Networking