Azure Load Balancer
Layer 4 TCP and UDP distribution with health probes, backend pools, NAT rules and the Standard SKU defaults.
Readiness
0%
2h baseline
Exam memorization points
- Azure Load Balancer is layer 4 and distributes TCP and UDP; it cannot inspect HTTP paths or hosts.
- Components: frontend IP configuration, backend pool, health probe, load-balancing rule, inbound NAT rule, outbound rule.
- Standard SKU is the default choice: zone-redundant, secure by default, supports HA ports and larger backend pools, and requires Standard public IPs.
- Public load balancers handle inbound internet traffic; internal (private) load balancers use a private frontend for intra-VNet traffic.
- Health probes can be TCP, HTTP or HTTPS with an interval and an unhealthy threshold; a failing probe removes the instance from rotation.
- Session persistence options are the default five-tuple, client IP two-tuple, and protocol-IP three-tuple.
Traps & distractors
- Mixing Basic and Standard SKUs across the public IP, the load balancer and the backend, which is not allowed.
- Forgetting that Standard load balancers are closed by default: without an NSG rule allowing the traffic, connections are dropped.
- Assuming a Standard internal load balancer provides outbound internet access. It does not; use a NAT Gateway or explicit outbound rules.
- Choosing Load Balancer for URL path routing. That requires Application Gateway.
- Ignoring the health probe path, which defaults to / and can mark healthy apps unhealthy.
Suggested lab
Internal load balancer with a real probe
Wire backends, probe and persistence, then prove failover.
- 1Create a Standard internal load balancer with a private frontend IP in the workload subnet.
- 2Add two web server VMs to the backend pool and an HTTP probe on /health.
- 3Add a load-balancing rule on port 80 and set session persistence to client IP.
- 4Stop the web service on one VM and confirm it is removed from rotation after the probe threshold.
- 5Compare the behaviour when the NSG blocks the probe port.
Microsoft Learn
- What is Azure Load Balancer?doc
- Search Microsoft Learn: Azure Load Balancer Standard SKU health probe session persistence outbound rulessearch
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%
Critical priority
High-yield and still weak. Study this next.
- 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 leverage32% × 20% = 6.5
2 later topics depend on it.
- 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
Baseline study time
2h
Complexity
3 / 5
Remaining to target
1h 42m
Status weight
0%
Topics: load balancer, l4, health probe, backend pool, session persistence, nat rule, ha ports
Weak neighbours in Networking