Azure IP Ranges and Network Security Best Practices

Understanding Azure IP Ranges is crucial for maintaining network security.

Azure provides a list of IP address ranges that can be used to configure firewalls and network security groups to allow or block traffic to and from Azure services.

To ensure secure communication between Azure services and your on-premises network, it's essential to allow traffic from the Azure IP ranges to your network.

A virtual network is a representation of your own network in the cloud, as provided by the Azure Virtual Network service.

Each virtual network you create has its own CIDR block, which is a unique range of IP addresses. You can link a virtual network to other virtual networks and on-premises networks as long as the CIDR blocks don't overlap.

To create a virtual network, you can provision and manage virtual private networks (VPNs) in Azure. Optionally, you can link virtual networks with other virtual networks in Azure, or with your on-premises IT infrastructure, to create hybrid or cross-premises solutions.

You have control over DNS server settings for virtual networks, along with segmentation of the virtual network into subnets. This allows you to customize your network configuration to suit your needs.

Here are the main use cases for virtual networks:

To create a virtual network, you can use the Azure portal, PowerShell, Azure CLI, or a network configuration file (netcfg) for classic virtual networks only.

You can use the Azure portal to create or configure a virtual network.

Here are the tools you can use to create or configure a virtual network:

To restrict access to Azure PaaS resources from a virtual network, you can use virtual network service endpoints or Azure Private Link.

When creating a virtual network, you have several tools at your disposal.

The Azure portal is one of the main tools you can use to create or configure a virtual network.

You can also use PowerShell to manage and configure your virtual network.

Alternatively, the Azure CLI is another option for creating and configuring virtual networks.

If you're working with classic virtual networks, a network configuration file (netcfg) is the tool you'll need to use.

Network and subnet size limits are an essential consideration when designing your Azure network configuration. The smallest supported IPv4 subnet is /29, and the largest is /2 (using CIDR subnet definitions).

Azure also supports IPv6 subnets, but they must be exactly /64 in size. This is a fixed requirement, so make sure to plan your IPv6 subnets accordingly.

For IPv4 subnets, the smallest size is /29, while the largest is /2. This gives you a good range of options for designing your network.

Here's a quick reference for the supported subnet sizes:

Keep in mind that Azure reserves the first four addresses and the last address, for a total of five IP addresses within each subnet. This is important to remember when planning your network and assigning IP addresses.

You can create a route table and associate it with a subnet. For more information about routing in Azure, see Custom routes.

To manage traffic flow, network security group (NSG) inbound rules are processed for inbound traffic, while NSG outbound rules are processed, followed by user-defined route (UDR) rules for outbound traffic.

A route table is the key to custom routing policies, allowing you to specify where traffic should be directed.

By creating a route table, you can define routes that are specific to your virtual networks and subnets, giving you more control over traffic flow.

You can modify a virtual network after creation, which is a big plus. This means you're not stuck with a network configuration that doesn't meet your needs.

You can add subnets to a virtual network at any time, as long as the subnet address range isn't part of another subnet and there's available space in the virtual network's address range. This gives you the flexibility to adjust your network configuration as needed.

One thing to keep in mind is that you can't have a subnet address range that's part of another subnet. This is a key condition for adding subnets to a virtual network.

You can also modify the CIDR blocks that a virtual network uses. This means you can add, remove, or change the IP address ranges used by your virtual network. This flexibility is useful if your network needs change over time.

Meraki Firewall Rules are a crucial part of network configuration, but they can be tricky to manage, especially when dealing with dynamic IP ranges.

Azure has a feature called service tags that can be used to specify a service without needing to specify a range of networks, making rules more maintainable.

You can't use service tags in Meraki to specify dynamic Azure networks, so you'll need to manually update the IP ranges on change.

This is the same for all firewalls, where the only dynamic lookups of IP's you can have the firewall perform is using FQDN's.

To manage a long list of IP networks, consider using policy objects in Meraki.

You can create a network object group and have a firewall rule reference it, then create a script to update the group on a schedule.

A script can also be used to import CSV files to build firewall rules and construct network objects and groups.

To keep up with Microsoft's updates to Azure IP ranges and service tags, you can create a script to download the updates and save them in the same CSV format as Meraki's network objects and groups.

Meraki's API allows you to update network appliance firewall rules and organization policy objects, but you'll need to manually trigger the script to update the rules.