Exercise - Configure network access

In this exercise, you configure the access to the virtual machine (VM) you created earlier in this module.

Warning

The VM for this exercise was createdly previously in this module. If you deleted the VM or resource group created in the prior lab, you'll need to run the following command:

az vm extension set --resource-group "IntroAzureRG" --vm-name my-vm --name customScript --publisher Microsoft.Azure.Extensions --version 2.1 --settings '{"fileUris":["https://raw.githubusercontent.com/MicrosoftDocs/mslearn-welcome-to-azure/master/configure-nginx.sh"]}' --protected-settings '{"commandToExecute": "./configure-nginx.sh"}'

Right now, the VM you created and installed Nginx on during the previous exercise isn't accessible from the internet. In this exercise, you'll create a network security group that changes that by allowing inbound HTTP access on port 80.

Note

It's important that you're in the BASH version of Cloud Shell for some of the commands in this exercise.

Task 1: Access your web server

In this procedure, you get the IP address for your VM and attempt to access your web server's home page.

Run the following az vm list-ip-addresses command to get your VM's IP address and store the result as a Bash variable:

IPADDRESS="$(az vm list-ip-addresses \
  --resource-group "IntroAzureRG" \
  --name my-vm \
  --query "[].virtualMachine.network.publicIpAddresses[*].ipAddress" \
  --output tsv)"

Run the following curl command to download the home page:

curl --connect-timeout 5 http://$IPADDRESS

The --connect-timeout argument specifies to allow up to five seconds for the connection to occur. After five seconds, you see an error message that states that the connection timed out:

curl: (28) Connection timed out after 5001 milliseconds

This message means that the VM wasn't accessible within the timeout period.

As an optional step, try to access the web server from a browser
Run the following to print your VM's IP address to the console:

echo $IPADDRESS

You will see an IP address, for example, 23.102.42.235.

Copy the IP address that you see to the clipboard.
Open a new browser tab and go to your web server. After a few moments, you see that the connection isn't happening. If you wait for the browser to time out, you see something like this:
Keep this browser tab open for later.

Task 2: List the current network security group rules

Your web server wasn't accessible. To find out why, let's examine your current NSG rules.

Run the following az network nsg list command to list the network security groups that are associated with your VM:

Azure CLI

az network nsg list \
  --resource-group "IntroAzureRG" \
  --query '[].name' \
  --output tsv

You see this output:

my-vmNSG

Every VM on Azure is associated with at least one network security group. In this case, Azure created an NSG for you called my-vmNSG.

Run the following az network nsg rule list command to list the rules associated with the NSG named my-vmNSG:

Azure CLI

az network nsg rule list \
  --resource-group "IntroAzureRG" \
  --nsg-name my-vmNSG

You see a large block of text in JSON format in the output. In the next step, you'll run a similar command that makes this output easier to read.

Run the az network nsg rule list command a second time. This time, use the --query argument to retrieve only the name, priority, affected ports, and access (Allow or Deny) for each rule. The --output argument formats the output as a table so that it's easy to read.
Azure CLI

az network nsg rule list \
  --resource-group "IntroAzureRG" \
  --nsg-name my-vmNSG \
  --query '[].{Name:name, Priority:priority, Port:destinationPortRange, Access:access}' \
  --output table

You see this output:

Output

Name              Priority    Port    Access
-----------------  ----------  ------  --------
default-allow-ssh  1000        22      Allow

You see the default rule, default-allow-ssh. This rule allows inbound connections over port 22 (SSH). SSH (Secure Shell) is a protocol that's used on Linux to allow administrators to access the system remotely. The priority of this rule is 1000. Rules are processed in priority order, with lower numbers processed before higher numbers.

By default, a Linux VM's NSG allows network access only on port 22. This port enables administrators to access the system. You need to also allow inbound connections on port 80, which allows access over HTTP.

Task 3: Create the network security rule

Here, you create a network security rule that allows inbound access on port 80 (HTTP).

Run the following az network nsg rule create command to create a rule called allow-http that allows inbound access on port 80:

Azure CLI

az network nsg rule create \
  --resource-group "IntroAzureRG" \
  --nsg-name my-vmNSG \
  --name allow-http \
  --protocol tcp \
  --priority 100 \
  --destination-port-range 80 \
  --access Allow

For learning purposes, here you set the priority to 100. In this case, the priority doesn't matter. You would need to consider the priority if you had overlapping port ranges.

To verify the configuration, run az network nsg rule list to see the updated list of rules:

Azure CLI

az network nsg rule list \
  --resource-group "IntroAzureRG" \
  --nsg-name my-vmNSG \
  --query '[].{Name:name, Priority:priority, Port:destinationPortRange, Access:access}' \
  --output table

You see both the default-allow-ssh rule and your new rule, allow-http:

Name              Priority    Port    Access
-----------------  ----------  ------  --------
default-allow-ssh  1000        22      Allow
allow-http          100        80      Allow

Task 4: Access your web server again

Now that you configured network access to port 80, let's try to access the web server a second time.

Note

After you update the NSG, it may take a few moments before the updated rules propagate. Retry the next step, with pauses between attempts, until you get the desired results.

Run the same curl command that you ran earlier:

curl --connect-timeout 5 http://$IPADDRESS

You see this response:

<html><body><h2>Welcome to Azure! My name is my-vm.</h2></body></html>

As an optional step, refresh your browser tab that points to your web server. You see the home page:

A screenshot of a web browser showing the home page from the web server. The home page displays a welcome message.

Nice work. In practice, you can create a standalone network security group that includes the inbound and outbound network access rules you need. If you have multiple VMs that serve the same purpose, you can assign that NSG to each VM at the time you create it. This technique enables you to control network access to multiple VMs under a single, central set of rules.

You've completed this exercise and all of the exercises for this module. To clean up your Azure environment and avoid leaving VMs running when not in use, delete the IntroAzureRG resource group.

Clean up

From the Azure home page, under Azure services, select Resource groups.
Select the IntroAzureRG resource group.
Select Delete resource group.
Enter IntroAzureRG to confirm deletion of the resource group and select delete.