Networking: Load Balancers

Question 1

Load Balancer: Backend pools

Answer 1

To distribute traffic, a back-end address pool contains the IP addresses of the virtual NICs that are connected to the load balancer

Question 2

Internal Load Balancer:

Answer 2

is used where private IPs are needed at the frontend only. Internal load balancers are used to load balance traffic inside a virtual network. A load balancer frontend can be accessed from an on-premises network in a hybrid scenario.

Question 3

Public Load Balancer:

Answer 3

Can provide outbound connections for virtual machines (VMs) inside your virtual network.

Public Load Balancers are used to load balance internet traffic to your VMs.

Maps the public IP address and port number of incoming traffic to the private IP address and port number of the VM.

Question 4

Azure Load Balancer:

Answer 4

The load balancer distributes inbound traffic to backend resources using load-balancing rules and health probes.

Question 5

Four components that must be configured for an Azure Load Balancer:

Answer 5

Frontend IP configuration, Backend pools, Health probes, and Load-balancing rules.

Question 6

Load Balancer rules

Answer 6

A load balancer rule defines how traffic is distributed to the backend pool. The rule maps a given frontend IP and port combination to a set of backend IP addresses and port combination.

Question 7

Azure Load Balancer: Session Persistence

Answer 7

Session persistence specifies how traffic from a client should be handled.

The default behavior (None) is that successive requests from a client may be handled by any virtual machine.

You can change this behavior.

Question 8

Azure Load Balancer: Health Probes

Answer 8

A health probe allows the load balancer to monitor the status of your app.

It dynamically adds or removes VMs from the load balancer rotation based on their response to health checks.

When a probe fails to respond, the load balancer stops sending new connections to the unhealthy instances.

Question 9

Azure Load Balancer: five-tuple hash

Answer 9

The hash is used to route traffic to healthy backend instances within the backend pool.

Source IP
Source Port
Destination IP
Destination Port
Protocol Type

Question 10

Load Balancer SKU: # Backend Pool Instances

Answer 10

Basic- 300,

Standard - 1000 instances

Question 11

Load Balancer SKUs: Health Probes

Answer 11

Basic- HTTP/TCP

Standard - HTTPS/HTTP/TCP

Question 12

Load Balancer SKUs: Availability Zones

Answer 12

Basic - No

Standard - Zone Redundant and zonal front ends for inbound and outbound

Question 13

Load Balancer SKUs: Multiple Front End restrictions

Answer 13

Basic - Inbound only

Standard - Inbound and Outbound

Question 14

Load Balancer SKUs: Default Security

Answer 14

Basic - Open by Default

Standard - Closed to inbound flows

Question 15

Load Balancer SKUs: SLA

Answer 15

Basic - None

Standard - 99.99%

Question 16

Load Balancer SKU: Backend Pools (Allowed Resources)

Answer 16

Basic SKU - Single VM, VM Scale Set, Availability Set

Standard SKU - Availability Set, Scale Set