Azure Accounts Wholesale How to configure Azure Virtual Network VNet

Introduction: Welcome to the Land of VNets (Population: You)

Configuring an Azure Virtual Network (VNet) is one of those tasks that sounds straightforward right up until you’re standing in the Azure portal staring at a screen full of options, wondering if “address space” is a metaphor for your life choices. The good news: you can configure a VNet cleanly, safely, and with enough foresight that future-you doesn’t have to undo everything with the emotional strength of a cartographer drawing a map during a hurricane.

This article provides a practical, readable walkthrough for configuring an Azure VNet. We’ll cover the essential decisions (address spaces, subnets, DNS, security, routing), plus the common add-ons (service endpoints, VNet peering, gateway connections). Along the way, I’ll point out common pitfalls, like overlapping IP ranges, forgetting DNS settings, and accidentally locking yourself out with an overzealous network security group.

Azure Accounts Wholesale Assume you want a VNet that can host virtual machines, allow traffic securely, and connect to other networks (either other VNets or on-premises) without turning connectivity into a suspense thriller.

What Is a VNet, Anyway?

An Azure Virtual Network (VNet) is your private network space inside Azure. It’s where you place resources (VMs, AKS nodes, app services with private endpoints, etc.) and control network behavior (IP addressing, subnets, routing, security rules).

Think of a VNet like an apartment building. The VNet is the building. Subnets are the floors. IP addresses are the apartment numbers. Network Security Groups (NSGs) are the doorman and the rules posted on the wall: who gets in, who doesn’t, and under what conditions.

Azure Accounts Wholesale Before You Touch the Portal: Plan Like a Responsible Adult

Azure won’t stop you from making questionable network designs. It will simply let you discover the consequences later, often during a “quick change” that takes three hours and a small existential crisis.

Here are the planning steps that will save you time:

• Choose an IP address range for your VNet that doesn’t overlap with other networks you’ll connect to (other VNets, on-premises networks, VPNs, etc.).
• Decide your subnet structure based on workload types (web, app, data, management) and growth.
• Pick a naming convention so you don’t end up with subnets called “Sub1,” “Sub1-2,” and “FinalSub.”
• Plan DNS behavior early, especially if you’ll use private endpoints, AD DS, or custom DNS servers.
• Define security rules and decide whether you’ll use NSGs at the subnet level, NIC level, or both.
• Consider routing needs like forced tunneling, UDRs (User Defined Routes), or peering requirements.

If you do nothing else, do this: avoid overlapping IP ranges. Overlapping IP ranges are like putting two identical keys on the same keyring and then acting surprised when every lock opens “sometimes.”

Step 1: Create a VNet

Start in the Azure portal (or use CLI/PowerShell if you prefer your infrastructure with less clicking and more confidence). The typical UI flow is:

• Go to Create a resource
• Select Networking and then Virtual network
• Choose the appropriate subscription and resource group
• Provide a VNet name, region, and settings

Subscription, Resource Group, and Region

Choose the region that matches where your workloads live. A VNet is tied to a region for the subnets inside it. If you plan to create multiple VNets, you can still connect them across regions using VNet peering, but the physical placement matters for latency and design.

Resource group naming should be consistent. For example: rg-network-prod, rg-app-prod, etc. It’s amazing how quickly the “temporary” resource group becomes a permanent museum exhibit.

Virtual Network Name and Address Space

Azure Accounts Wholesale Your VNet’s address space is the overall block of IP addresses available in the VNet. For example, you might pick something like:

• Address space: 10.20.0.0/16

Azure Accounts Wholesale That gives you 65,536 addresses (because networking loves round numbers just enough to be tempting). Then you carve that into subnets, like 10.20.1.0/24, 10.20.2.0/24, and so on.

Key advice: pick a range that won’t collide with existing networks. If your on-premises network uses 10.20.0.0/16 already, don’t choose the same. Overlaps cause routing ambiguity and can break connectivity in ways that feel personal.

Choose the IP Version (IPv4 vs IPv6)

Most setups start with IPv4. If you need IPv6, plan early because it affects design choices, DNS, and connectivity patterns.

Azure Accounts Wholesale If you’re unsure, stick with IPv4 unless your organization has a clear IPv6 roadmap. You can always extend later, but start with a plan that won’t require heroics.

Subnets (The “Floors” of Your Building)

When creating the VNet, Azure often asks for subnet configuration. You can create one or more subnets right away.

For a typical application network, a common pattern is:

• Management subnet: 10.20.10.0/24 (jumpboxes, bastion, admin tools)
• Web subnet: 10.20.20.0/24 (web servers, ingress)
• App subnet: 10.20.30.0/24 (application services)
• Azure Accounts Wholesale Data subnet: 10.20.40.0/24 (databases, private endpoints)

You can adjust based on workload. The critical point is to design for growth. If you create a /24 for something that might expand, you might be forced into awkward subnet resizing later. Resizing subnets isn’t always fun, so try to give yourself headroom.

Step 2: Understand and Set Subnet Properties

After you create the VNet, you can configure details for each subnet. Some properties are essential; others are situational.

Subnet Delegation (When You Need Special Permissions)

Subnet delegation allows certain Azure services to use a subnet. Examples include:

• Azure App Service (where applicable)
• AKS (Azure Kubernetes Service)
• Private endpoints (in certain configurations)

Delegation is like giving a specific tenant a set of keys and permission to remodel their space. It’s not needed for every subnet, but it becomes required when you want particular services to deploy into that subnet.

Service Endpoints and Private Link (Advanced but Useful)

Service endpoints let your subnet reach certain Azure services securely without going through the public internet. Private endpoints go further: they map the service to a private IP inside your VNet.

If you use private endpoints, you usually want the destination subnet to be designed for that (and you’ll need to configure private DNS zones and linking). Private Link is fantastic—until you forget DNS linking, then you get the classic symptom: “It’s in the network, but it can’t be found.”

Network Security Group (NSG) Assignment at the Subnet Level

Many teams attach NSGs directly to subnets. That means all NICs inside the subnet inherit those security rules (though NIC-level NSGs can override or add additional rules).

You’ll create the NSG later in detail, but at a minimum, decide whether you’ll:

• Attach NSGs to subnets (good for baseline controls)
• Attach NSGs to network interfaces (good for per-instance rules)
• Use a combination (common in mature environments)

Step 3: Set Up DNS Correctly (Because “Name Resolution” Is Not Optional)

DNS in Azure can be handled in a few ways depending on your setup:

• Azure-provided DNS (default)
• Custom DNS servers
• Private DNS zones for private endpoints

Choosing a DNS approach late can cause more rework than changing a password after you’ve already shared it. So let’s do it right.

Azure-Provided DNS vs Custom DNS Servers

By default, Azure uses its own DNS. For many workloads, this is sufficient, especially when you don’t have custom name resolution requirements.

If your organization has custom internal DNS (for example, AD DS or other internal zones), you might configure your VNet to use custom DNS servers. That typically involves specifying the DNS server IP addresses.

When using custom DNS, ensure the servers are reachable from your VMs (routing, firewall rules, etc.). If DNS servers aren’t reachable, your VMs can still boot—but your applications will behave like toddlers searching for snacks that aren’t in the house.

Private DNS Zones for Private Endpoints

When you create private endpoints, you typically create and link private DNS zones so that your services resolve to private IPs.

For example, a private endpoint for a storage account might require a private DNS zone like:

• privatelink.blob.core.windows.net or similar

Then you link the private DNS zone to your VNet(s). After that, clients in the VNet can resolve the storage account hostname to the private endpoint IP.

Forgetting DNS zone linking is the most common cause of “Private endpoint is configured, but connections fail.” The private IP exists, but nobody can find it by name.

Step 4: Create Network Security Groups (NSGs) Like You Mean It

NSGs control inbound and outbound traffic at the subnet or network interface level. They’re not meant to replace all security controls, but they do a lot of important blocking.

Inbound vs Outbound Rules

Azure NSGs have default rules. Typically, there’s an implicit deny for inbound traffic unless allowed by rules, and outbound traffic is usually allowed unless explicitly restricted (or vice versa depending on default rule structure).

When you add rules, you’ll choose:

• Priority (lower number = higher priority)
• Source (IP range or tag)
• Destination (often the subnet or service)
• Port(s)
• Protocol (TCP/UDP/Any)
• Action (Allow or Deny)

Priority matters. If you create two rules that could match the same traffic, Azure uses the lowest priority number rule. That’s like picking the loudest voice in a meeting to decide policy.

A Practical NSG Rule Set for a Web Subnet

Let’s say your web subnet hosts VMs that accept HTTP/HTTPS from the internet through a load balancer or ingress pattern. A simplified approach might be:

• Inbound allow TCP 80 from Internet (or from a specific load balancer IP range)
• Inbound allow TCP 443 from Internet (or from a specific load balancer IP range)
• Inbound deny everything else (or let default handle it)
• Outbound allow to required services (DNS, storage, API endpoints, etc.)

For management, you’ll often restrict SSH/RDP access to your admin IP range, or better yet use a bastion host or VPN connectivity. Nobody wants “RDP exposed to the entire world, because why not” to be your company’s security story.

NSG Rules for SSH/RDP (Limited and Boring)

If you allow SSH (22) or RDP (3389), limit them:

• Source: your office IP(s) or VPN address range
• Protocol: TCP
• Port: 22 or 3389

Also consider auditability. Logging and monitoring are your future teammates. NSGs are the bouncer; you still want cameras.

Step 5: Route Tables (UDRs) for When Default Routing Isn’t Enough

Azure provides default routing between subnets and out to the internet through gateways depending on configuration. But sometimes you need more control. That’s where route tables and User Defined Routes (UDRs) come in.

Why You Might Need UDRs

• Forced tunneling: sending all traffic to a firewall appliance or security gateway
• Custom routing between subnets or to virtual appliances
• Traffic inspection requirements

If you’re not sure whether you need UDRs, you probably don’t. But if you do need them, plan carefully because misroutes are a classic “everything is configured correctly except the packet still can’t reach its destination” situation.

Creating and Associating a Route Table

A typical flow:

• Create a route table
• Add routes (destination prefixes and next hop types)
• Associate the route table to a subnet

Next hop might be:

• Azure Accounts Wholesale Internet
• Virtual network gateway
• Virtual appliance (e.g., firewall)
• None (to block certain routes)

Make sure the next hop destination is reachable. If your route table points to a virtual appliance IP that doesn’t exist or isn’t accessible, your traffic will go on a road trip to nowhere.

Step 6: Enable Connectivity Between Subnets (and VNets)

Connectivity can be layered: subnet-to-subnet inside a VNet, VNet peering to another VNet, and gateway connectivity to on-premises networks.

Subnet-to-Subnet Inside the Same VNet

By default, subnets in the same VNet can communicate according to NSG rules. Routing within the VNet is straightforward unless you added UDRs.

Azure Accounts Wholesale So if traffic fails between subnets, the usual suspects are:

• NSG denies the traffic
• Application is listening on a different port/interface
• Firewall rules inside the VM
• Wrong IP/hostname resolution

VNet Peering (Connect Buildings Without Building a Bridge)

VNet peering connects two VNets so that resources in one VNet can communicate with resources in the other as if they were on the same network, subject to NSG rules and routing.

When configuring peering:

• Ensure address spaces do not overlap (again, overlap is the villain)
• Create peering from VNet A to VNet B
• Create peering from VNet B to VNet A (peering is reciprocal)
• Choose whether to allow forwarded traffic
• Choose whether to allow gateway transit (usually not needed for simple peering)

Peering is a great option when you want connectivity without a full gateway. If you later need on-premises connectivity, a gateway might still be part of your architecture.

When VNet Peering Is Not Enough

Peering does not replace a VPN or ExpressRoute gateway for on-premises connectivity. If you need to connect to corporate networks, you’ll likely use:

• Site-to-site VPN
• ExpressRoute
• Point-to-site VPN (for remote users)

These involve a Virtual Network Gateway and local network gateway definitions.

Step 7: Gateways for On-Premises Connectivity (Optional, but Common)

If your VNet must connect to on-premises, you configure a Virtual Network Gateway (for Azure) and a corresponding local network gateway (for on-premises).

VPN Gateway Basics

A common pattern for site-to-site VPN:

• Create a Virtual Network Gateway in the VNet (usually in a dedicated gateway subnet)
• Configure the VPN device details on-premises (public IP, tunnel settings)
• Define local network gateway with on-premises address prefixes
• Create the connection resource to link both sides

Important: gateway subnet usually has a dedicated IP range, and you must configure it according to Azure’s requirements.

Gateway Subnet Planning

Your gateway subnet is not like your app subnets. It’s a special subnet for the gateway, and Azure expects it to exist with a specific name and size.

If you get this wrong, Azure will let you know—eventually, after you’ve spent time planning the wrong way. So read the requirement carefully before finalizing.

Step 8: Validate Your Configuration (So You Don’t Guess)

Validation is where you earn your sanity back. After configuration, test connectivity deliberately.

Use Azure Network Watcher Tools

Azure includes tools like Network Watcher features to help validate routing and connectivity. Depending on your subscription and setup, you can:

• Check effective routes (what routes a VM uses)
• Verify next hop and reachability
• Use packet capture (where supported)
• Test IP flow with diagnostics

Instead of “it doesn’t work” (the most expensive phrase in IT), you want “the NSG denies inbound TCP 443 from 203.0.113.10” or “the effective route shows traffic goes to the firewall appliance, but the appliance IP isn’t reachable.” That turns mystery into a checklist.

Basic Connectivity Tests

• From a test VM: try reaching internal IPs by name and by IP
• Test DNS resolution: nslookup/dig
• Test ports: curl for HTTP/HTTPS, Test-NetConnection in PowerShell, etc.
• Check NSG flow logs or diagnostic logs if traffic is denied

Remember: NSG denies are not personal. They’re just following the rules you wrote at 2 a.m. with a coffee that tasted like regret.

Common Pitfalls (A Greatest Hits Album of Network Problems)

Here are frequent mistakes people make when configuring VNets. If you’ve ever made one of these, congratulations—you’re now part of the human race.

1) Overlapping Address Spaces

If you plan to peer VNets or connect on-premises, verify address ranges across everything. Overlaps can break routing or prevent peering.

2) Forgetting DNS for Private Endpoints

Private endpoints require correct DNS zone linking and client resolution. Without that, connections fail by hostname even though the private IP exists.

3) Overly Restrictive NSG Rules

It’s easy to write an NSG rule that blocks more than you intended. A typical symptom is “The web server is up, but I can’t reach it,” while logs show inbound traffic denied.

Start with a minimal allow policy and expand carefully.

4) Wrong Priority in NSG Rules

Priority order can cause your “allow” rule to be ignored because a “deny” rule matches first (lower numeric priority).

5) No Plan for Outbound Traffic

Many environments need outbound access for Windows updates, package downloads, DNS, and calling other services. If you lock down outbound too tightly, you’ll see strange application errors later.

Consider the required outbound patterns early.

6) Route Tables Without Reachable Next Hop

If you configure UDRs pointing to a virtual appliance, confirm that the appliance exists, is reachable, and is configured for forwarding/inspection.

Suggested Reference Architecture (Example You Can Adapt)

Here’s a “reasonable default” VNet structure many teams use as a starting point. Adapt it to your environment and constraints.

• VNet: 10.20.0.0/16
• Subnets:
• mgmt: 10.20.10.0/24 (admin jumpbox / bastion access)
• web: 10.20.20.0/24 (web tier)
• app: 10.20.30.0/24 (app tier)
• data: 10.20.40.0/24 (database / private endpoints)
• NSGs:
• web NSG allows inbound 80/443 from load balancer or specific ranges
• app NSG allows inbound from web subnet only on required ports
• data NSG allows inbound only from app subnet (and required ports)
• mgmt NSG allows SSH/RDP only from admin IPs or via bastion
• Azure Accounts Wholesale DNS:
• Use Azure DNS or configure custom DNS if required
• If private endpoints: create and link private DNS zones

This structure creates separation between tiers and makes troubleshooting more logical. It’s like labeling every drawer in your desk instead of tossing everything into “miscellaneous.”

Automation Tip: Treat Your VNet as Code

Clicking through the portal is fine for learning. But for repeatability, consider infrastructure-as-code (IaC) using ARM templates, Bicep, Terraform, or the Azure CLI.

Why? Because:

• You’ll recreate consistent networks across environments (dev/test/prod).
• You’ll reduce configuration drift.
• You’ll document decisions in code.

Also, if you ever need to fix something, “change the code and redeploy” is far less painful than “scroll through six tabs and hope you remember what that checkbox did.”

Security and Compliance Notes (No, You Can’t “Just Set It to Allow All”)

While NSGs provide network-level control, remember that security is layered. Your application still needs:

• Authentication and authorization
• Least privilege for services (managed identities, roles, etc.)
• Patch and vulnerability management
• Monitoring and logging

VNets and NSGs are the physical security doors. They’re not the whole building.

Mini Checklist: VNet Configuration Done Right

• Address space planned and non-overlapping
• Subnets sized with growth in mind
• DNS strategy chosen (Azure DNS vs custom vs private DNS zones)
• NSGs created with explicit allow rules for required traffic
• NSGs associated to the correct subnets (or NICs)
• UDRs and route tables used only when needed, with reachable next hops
• VNet peering configured properly (reciprocal, correct settings)
• Connectivity tested using effective routes, DNS tests, and port checks

If you can check all of those boxes without sweating through your shirt, you’re doing better than most of us.

Conclusion: Your Network Is Now a Calm Place to Live

Configuring an Azure Virtual Network doesn’t have to feel like solving a riddle written by a committee of gremlins. With careful planning (address spaces, subnets, DNS, security, and routing), you can create a VNet that is structured, secure, and ready to connect to other networks.

Start simple: build the VNet, carve out subnets, attach NSGs, and ensure DNS is correct. Then add features like peering, private endpoints, and gateways when you truly need them. Most importantly, validate with testing tools so you don’t rely on hope as a network protocol.

Now go forth and configure your VNet like the responsible wizard of IP addresses you were always meant to be.