Azure Networking Learning Path Essentials and Best Practices

To get started with Azure Networking, it's essential to understand the core components, including Virtual Networks (VNets), Subnets, and Network Security Groups (NSGs).

Azure VNets are the fundamental building blocks for networking in Azure, and they can be used to create isolated networks for different environments or applications.

A VNet can be thought of as a logical network that can be used to connect multiple resources, such as virtual machines and storage accounts.

NSGs are used to filter network traffic and can be applied to subnets or individual network interfaces.

To ensure secure communication between resources, it's crucial to use NSGs to control inbound and outbound traffic.

By applying best practices, such as using NSGs and configuring VNets correctly, you can create a secure and scalable networking infrastructure in Azure.

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Azure VNets are the fundamental building blocks for your private network in Azure, enabling Azure resources to securely communicate with each other, the internet, and on-premises networks. Each VNet is created by specifying a custom private IP address space using public and private (RFC 1918) addresses.

A VNet can have up to 50-100 VNets allowed per Azure Subscription, and it's essential to include the environment and region in the VNet name for better organization. Each VNet is created by specifying a custom private IP address space using public and private (RFC 1918) addresses, and a portion of the virtual network's address space is allocated to subnets to deploy Azure resources.

Here's a breakdown of the host CIDR range, bits, and addresses:

Azure VNets manage User defined routes (UDR's) and can be connected to on-premises networks using an Azure VPN Gateway or ExpressRoute.

In this course, you'll learn the fundamentals of Azure networking, including designing and implementing Azure virtual networks.

You'll start with an introduction to Azure virtual networks, which is covered in Module 1 of the course.

Module 2 focuses on designing and implementing hybrid networking, a crucial aspect of Azure networking.

Module 3 is dedicated to designing and implementing Azure ExpressRoute, a high-bandwidth, low-latency connectivity solution.

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To balance non-HTTP(S) traffic in Azure, you'll learn how to load balance in Module 4.

Module 5 covers load balancing HTTP(S) traffic in Azure, a critical task for ensuring smooth and secure network operations.

Designing and implementing network security is the focus of Module 6, where you'll learn how to protect your Azure network from threats.

Module 7 teaches you how to design and implement private access to Azure Services, ensuring secure and controlled access to your cloud resources.

To monitor your Azure network, you'll learn how to design and implement network monitoring in Module 8.

Here's a summary of the course subjects:

Azure uses two types of IP addresses: Public IP and Private IP. Private IP addresses are used for communication within the Azure resource group, while Public IP addresses allow Azure resources to communicate with public-facing Azure services via the Internet.

In Azure, IP addresses can be allocated using either Dynamic IP or Static IP. Dynamic IP is the default allocation method, where Azure automatically assigns an available and unreserved IP address from the subnet's address range. Static IP, on the other hand, is a custom allocation method where you can assign a specific IP address from the subnet's address range.

CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses, which involves applying a subnet mask to an IP address. This mask defines the number of bits used as a network and the host bits left.

Azure VNets define the communications and security boundaries that enable Azure resources to communicate with each other securely. VNets are created by specifying a custom private IP address space using public and private (RFC 1918) addresses.

A subnet is a part of a network that covers a range of IP addresses. In Azure, VNets can be divided into smaller subnets for organizations. Each subnet consists of a server and can be further divided into Private and Public subnets.

Here's a breakdown of the CIDR block ranges:

Azure takes the first 3 and the last address of each subnet for its own, leaving the remaining addresses for use by Azure resources.

DNS is a crucial aspect of Azure networking, and understanding how it works can help you manage your virtual networks more effectively. Azure provides three methods for resolving domain names to internal IP addresses: Azure DNS private zones, Azure-provided name resolution, and custom-managed DNS servers.

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Azure DNS private zones is the preferred solution due to its flexibility in managing DNS zones and records. It's especially useful when you need to manage DNS zones and records for your virtual networks.

Azure-provided name resolution provides high availability with no configuration required, but it only provides basic authoritative DNS capabilities. However, it does automatically apply appropriate DNS suffixes to virtual machines.

Custom-managed DNS servers, on the other hand, allow you to forward queries to the Azure-provided DNS servers. This can be useful when you need to resolve names between different virtual networks or between your on-premises network and Azure.

In virtual networks deployed using the Azure Resource Manager (ARM) deployment model, the DNS suffix is consistent across all virtual machines within a virtual network. This means you don't need to use Fully Qualified Domain Names (FQDN) to resolve names.

Here are the three methods for resolving domain names to internal IP addresses in Azure virtual networks:

VMs and instances in a cloud service share the same DNS suffix, so the host name alone is sufficient for resolving names within the same cloud service. However, in virtual networks deployed using the classic deployment model, different cloud services have different DNS suffixes, so you need to use FQDN to resolve names between different cloud services.

Role instances can perform name resolution of VMs within the same virtual network by using the FQDN, which consists of the VM's host name and internal.cloudapp.net DNS suffix. However, name resolution is only successful if the role instance has the VM name defined in the Role Schema (.cscfg file).

For another approach, see: How to Change Virtual Network/subnet in Azure Vm

ICMP Ping Verification is a crucial step in ensuring network connectivity within Azure Virtual Networks (VNets).

To enable ICMP pings on each VM, use this PowerShell command: Set-ExecutionPolicy -ExecutionPolicy Bypass -Force New-NetFirewallRule -DisplayName 'Allow ICMPv4-In' -Protocol 'ICMPv4'.

Azure blocks ICMP between VNets and the internet, so we need to allow it on each VM. This command does just that.

Once ICMP is enabled, you can test whether another VM can reach another VM by entering a PowerShell session on one of the VMs and running the command ping -4 10.20.20.1.

If you're having trouble reaching a VM using ICMP, you can try using the TCP protocol instead by running “tcoping” from SysInternals. This is a great alternative when ICMP is blocked.

Here are some common uses for tcping.exe:

Azure Networking Features offer a range of benefits, including secure connectivity and improved security. With Service Endpoints, you can connect to Azure services without needing a public IP address, making it a simple and secure option.

Service Endpoints allow Private IP addresses in a VNet to reach the endpoint of an Azure Service, improving security for Azure resources in a network. This feature is particularly useful for Azure Storage and Azure Database services.

Virtual Network peering enables you to connect two or more Virtual Networks in Azure, allowing data transfer between deployment models, subscriptions, and regions without downtime or failure. This is achieved through Microsoft's backbone infrastructure and a private network.

There are two types of Virtual Network Peering: Regional VNet Peering and Global VNet Peering. Regional VNet Peering connects networks in the same region, while Global VNet Peering connects networks across different regions.

Here are some key Azure Networking Features:

Note that VNet pricing can be quite expensive, with a monthly cost of $80,000.

In Azure, a Network Interface (NIC) is a virtual ethernet card that enables communication between Virtual Machines in a network.

The NIC is automatically created when a Virtual Machine is created in Azure, with default settings.

You can customize Network Interface settings in Azure using command tools like Azure CLI and PowerShell.

Typically, Virtual Machines are set up as a cluster behind a Load Balancer, so most VMs don't accept traffic directly from the public internet.

To add multiple NICs for load balancers or isolation, a VM needs to be in stopped or deactivated state.

You can use PowerShell to add a network interface, and each CIDR can be configured with up to 50 IP address ranges.

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Service Endpoints in Azure provide secure connectivity over the optimized route of the Azure Network.

With Service Endpoints, you don't need a public IP address to connect to Azure Services. This improves security for Azure resources in your network.

Service Endpoints can be used to connect Private IP addresses in a VNet to the endpoint of an Azure Service, such as Azure Storage or Azure Database.

Here are some key benefits of using Service Endpoints:

VNet Peerings are a powerful feature in Azure that enable you to connect two or more Virtual Networks, allowing data to be transferred between them without downtime or failure.

You can create two types of VNet Peerings: Regional VNet Peering and Global VNet Peering. Regional VNet Peering connects two networks in the same region, while Global VNet Peering connects networks in different regions.

Regional VNet Peering is faster and more cost-effective than Global VNet Peering, but it's limited to networks within the same region. Global VNet Peering, on the other hand, allows for cross-region connectivity and is ideal for scenarios that require data replication or database failover.

Here are the key differences between Regional and Global VNet Peering:

To set up VNet Peering, you need to create a peering connection between the two networks. This involves creating a peer relationship between the two networks and configuring the peering settings.

To create a peer relationship, you need to grant the peer subscription's administrator the Network Contributor role on your virtual network. This will allow them to manage the peering connection and configure the settings.

Once the peering connection is established, you can create virtual machines on each network and test communication between them using Network Watcher.

Remember, peering connections are not transitive, meaning that if network A is peered with network B and network B is peered with network C, network A cannot talk to network C without using Gateway Transit.

Zone-redundant gateways bring resiliency, scalability, and higher availability to virtual network gateways by physically and logically separating gateways within a region.

This configuration protects on-premises network connectivity to Azure from zone-level failures, making it a crucial feature for businesses that require high uptime.

To deploy gateways in a zone-redundant configuration, you'll need to select a region that supports availability zones and use different gateway SKUs.

You'll also need to leverage Standard public IP addresses instead of Basic public IP addresses.

By implementing zone-redundant gateways, you can ensure that your network remains accessible even in the event of a zone-level failure.

Here are the key benefits of zone-redundant gateways:

Public IP Configuration is a crucial aspect of Azure Networking Features. You can allocate a public IP address to your Azure resources, allowing them to communicate with public-facing services via the internet.

There are two types of public IP addresses: Public and Private. Public IP addresses enable Azure Resources to communicate with public-facing Azure services via the internet, while Private IP addresses allow communication of resources within the Azure resource group.

To configure a public IP address, you can follow these steps. First, set up a Network Security Group (NSG) to protect your VM's network interface. This will help ensure the security of your network.

Here are the types of IP allocation methods available in Azure:

When configuring a static public IP address, you'll need to select the "Static" assignment method and specify a specific IP address. This will ensure that the IP address remains fixed and doesn't change with time.

Note that a reboot of the VM is necessary when the IP changes. This is an important consideration when working with static public IP addresses.

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Custom DNS Servers allow VMs to see both on-premises resources and Azure-provided host names by forwarding queries to Azure's recursive resolvers via the virtual IP 168.63.129.16.

In order to resolve a VM's host name, the DNS server VM must reside in the same virtual network and be configured to forward host name queries to Azure.

Conditional forwarding rules send DNS queries to the correct virtual network for resolution, making it possible for resources in virtual networks to resolve domain names to internal IP addresses.

This method is particularly useful for role instances that need to perform name resolution of VMs in another virtual network, as it enables DNS resolution between virtual networks.

A custom DNS server can forward queries to Azure's DNS servers, which provides high availability with no configuration required.

Here are the three methods for resources in virtual networks to resolve domain names to internal IP addresses:

Custom-managed DNS servers can be used in virtual networks deployed using the Azure Resource Manager (ARM) deployment model, where the DNS suffix is consistent across all virtual machines.

Front Door provides routing by Layer 7 URLs with session affinity, URL redirection, and URL rewrite. It uses TCP-based anycast protocol to ensure connection to the closest endpoint.

Azure Front Door can handle IPv6 and HTTP/2 traffic, making it a versatile solution. It can also handle certificate management and perform TLS termination, sending HTTP traffic downstream.

Unlike some other solutions, Azure Front Door doesn't route by geo (DNS). This means you can use it to distribute traffic to different regions without worrying about DNS configuration.

Here are some key features of Azure Front Door:

Azure Front Door is a powerful tool for routing traffic to different regions and ensuring high availability. It's a great option to consider when designing your Azure networking infrastructure.

Load Balancers are a crucial component of Azure Networking Features, allowing you to distribute incoming traffic across multiple resources such as virtual machines.

Azure Load Balancers direct Layer 4 incoming traffic based on a 5-tuple hash to multiple resources such as virtual machines. To create a Load Balancer, you can use the Azure Portal, where you can create a resource, select Networking, and then choose Load Balancer from the Azure Marketplace.

When creating a Load Balancer, you'll need to specify a front-end, which can be either internal or public, and choose a type of VNet and subnet. You can also assign a dynamic IP address to the Load Balancer.

A backend pool is a target for Load Balancers to direct their incoming traffic to, and it contains at least one target, such as a web server on a virtual machine. To distribute traffic to the VMs, a backend address pool contains the IP addresses of the virtual (NICs) connected to the Load Balancer.

Here are the key settings to configure for a Load Balancer:

Each VM is attached to one of two network interfaces which accept and send traffic, allowing the Load Balancer to alternate traffic between virtual machines in the backend pool.