Configure name resolution and Load balancing

Question 1

What is Azure DNS

Answer 1

A hosting service for DNS domains that provides name resolution by Microsoft infrastructure.

1.You can not register a domain name using Azure DNS. You can buy a name by using app service domains or third party domain name registrar

2. Once that is done you can then host your domain in azure DNS by delegating the domain to azure DNS from parent domain

• DNS forwarder is created by creating a DNS zone in azure. DNS zones are used to resolve DNS names to IP addresses.

-SOA - is automatically created when a DNS zone is created and contains information about you DNS zones.

• Reverse lookup zone is used to convert IP address to domain names.

*NS record represents the name server that hosts the DNS zone for a DNS domain. You have to Create a name server record in your registrar to point to azure-dns servers

DNS uses both TCP and UDP . DNS requires communications over UDP as the primary protocol.
- If the DNS resolution times out over UDP , DNS will send the request over TCP but this will cause delays and slow resolution

Question 2

Configure Azure DNS
https://learn.microsoft.com/en-us/azure/dns/dns-web-sites-custom-domain

https://learn.microsoft.com/en-us/azure/dns/dns-zones-records

Answer 2

Private DNS and public DNS

1. Private DNS
   Manages and resolves domain names in the virtual network with out the need to configure a custom DNS solution

• Azure DNS allows you to create private , non-publicly routable DNS zones that are bound to one or more VNets

Steps for on hosting you domain:
1.You can not register a domain name using Azure DNS. You can buy a name by using app service domains or third party domain name registrar.

2. Create a zone
3. Configure DNS records
4. Create a name server record in your registrar to point to azure-dns servers

Question 3

What is a load balancer?

Answer 3

Distributing incoming network traffic across a group of backend servers or resources.

Frontend load balancer( Internal)

Backend load balancer( Public facing)

Question 4

Configure internal or Public load balancer

Answer 4

Public load balancer:
-Provides outbound connections for vm inside your virtual network.
- Translates the private ip address of vm to a public ip.
- Used to load balance internet traffic to your vm’s

Internal or Private Load Balancer:
- used to load balance traffic inside a virtual network
- Load Balancer frontend can be accessed from an on prem network in a hybrid scenario

• When a STANDARD load balancer is assigned multiple public IP it will use all assigned IP addresses at the same time
• When a BASIC load balancer is assigned multiple public ip address all public IP’s are taken into consideration , but only one is used for the outbound flow

Question 5

Load Balancer SKUs

Answer 5

Standard , basic and gateway

Standard:
Equipped for load-balancing network layer traffic when high performance and ultra-low latency is needed. Routes traffic within and across regions, and to availability zones for high resiliency.

• Multiple frontends - Inbound and outbound

Basic:
Equipped for small-scale applications that don’t need high availability or redundancy. Not compatible with availability zones.

• Multiple frontends - Inbound only

Question 6

Troubleshoot load balancing

Answer 6

https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-troubleshoot-backend-traffic