AZ-700 Designing and Implementing Microsoft Azure Networking Solutions Questions and Answers

Here are the steps and explanations for ensuring that all hosts deployed to subnet3-2 connect to the internet by using the same static public IP address:

To use the same static public IP address for multiple hosts, you need to create a NAT gateway and associate it with subnet3-2. A NAT gateway is a resource that performs network address translation (NAT) for outbound traffic from a subnet1. It allows you to use a single public IP address for multiple private IP addresses2.

To create a NAT gateway, you need to go to the Azure portal and select Create a resource. Search for NAT gateway, select NAT gateway, then select Create3.

On the Create a NAT gateway page, enter or select the following information and accept the defaults for the remaining settings:

Subscription: Select your subscription name

Resource group: Select your resource group

Name: Type a unique name for your NAT gateway

Region: Select the same region as your virtual network

Public IP address: Select Create new and type a name for your public IP address. Select Standard as the SKU and Static as the assignment method4.

Select Review + create and then select Create to create your NAT gateway3.

To associate the NAT gateway with subnet3-2, you need to go to the Virtual networks service in the Azure portal and select your virtual network.

On the Virtual network page, select Subnets under Settings, and then select subnet3-2 from the list.

On the Edit subnet page, under NAT gateway, select your NAT gateway from the drop-down list. Then select Save.

Here are the steps and explanations for ensuring that requests for wwwjelecloud.com from any of your Azure virtual networks resolve to frontdoor1.azurefd.net:

To use a custom domain with your Azure Front Door, you need to create a CNAME record with your domain provider that points to the Front Door default frontend host. A CNAME record is a type of DNS record that maps a source domain name to a destination domain name1.

To create a CNAME record, you need to sign in to your domain registrar’s website and go to the page for managing DNS settings1.

Create a CNAME record with the following information1:

Source domain name: wwwjelecloud.com

Destination domain name: frontdoor1.azurefd.net

Save your changes and wait for the DNS propagation to take effect1.

To verify the custom domain, you need to go to the Azure portal and select your Front Door profile. Then select Domains under Settings and select Add2.

On the Add a domain page, select Non-Azure validated domain as the Domain type and enter wwwjelecloud.com as the Domain name. Then select Add2.

On the Domains page, select wwwjelecloud.com and select Verify. This will check if the CNAME record is correctly configured2.

Once the domain is verified, you can associate it with your Front Door endpoint. On the Domains page, select wwwjelecloud.com and select Associate endpoint. Then select your Front Door endpoint from the drop-down list and select Associate2.

Here are the steps and explanations for ensuring that subnet4-3 can accommodate 507 hosts:

To determine the subnet size that can accommodate 507 hosts, you need to use the formula: number of hosts = 2^(32 - n) - 2, where n is the number of bits in the subnet mask1. You need to find the value of n that satisfies this equation for 507 hosts.

To solve this equation, you can use trial and error or a binary search method. For example, you can start with n = 24, which is the default subnet mask for Class C networks. Then, plug in the value of n into the formula and see if it is too big or too small for 507 hosts.

If you try n = 24, you get number of hosts = 2^(32 - 24) - 2 = 254, which is too small. You need to increase the value of n to get a larger number of hosts.

If you try n = 25, you get number of hosts = 2^(32 - 25) - 2 = 510, which is just enough to accommodate 507 hosts. You can stop here or try a smaller value of n to see if it still works.

If you try n = 26, you get number of hosts = 2^(32 - 26) - 2 = 254, which is too small again. You need to decrease the value of n to get a larger number of hosts.

Therefore, the smallest value of n that can accommodate 507 hosts is n = 25. This means that the subnet mask for subnet4-3 should be /25 or 255.255.255.128 in dot-decimal notation1.

To change the subnet mask for subnet4-3, you need to go to the Azure portal and select your virtual network. Then select Subnets under Settings and select subnet4-3 from the list2.

On the Edit subnet page, under Address range (CIDR block), change the value from /24 to /25. Then select Save2.

To create an Azure Firewall instance, you need to go to the Azure portal and select Create a resource. Type firewall in the search box and press Enter. Select Firewall and then select Create1.

To assign an IP address from the address range of 10.1.255.0/24 to the firewall, you need to select a public IP address that belongs to that range. You can either create a new public IP address or use an existing one1.

To use a new Premium firewall policy named FW-policy1, you need to select Premium as the Firewall tier and create a new policy with the name FW-policy12. A Premium firewall policy allows you to configure advanced features such as TLS Inspection, IDPS, URL Filtering, and Web Categories3.

To route traffic directly to the internet, you need to enable SNAT (Source Network Address Translation) for the firewall. SNAT allows the firewall to use its public IP address as the source address for outbound traffic4.

planation:

To achieve the task of ensuring that virtual machines on VNET1 and VNET2 are included automatically in a DNS zone named contoso.azure, and that they can resolve the names of the virtual machines on either virtual network, you can follow these steps:

Step-by-Step Solution

Step 1: Create a Private DNS Zone

Navigate to the Azure Portal.

Search for “Private DNS zones” in the search bar and select it.

Click on “Create”.

Enter the DNS zone name as contoso.azure.

Select the appropriate subscription and resource group.

Click on “Review + create” and then “Create”.

Step 2: Link VNET1 and VNET2 to the DNS Zone

Go to the newly created DNS zone (contoso.azure).

Select “Virtual network links” from the left-hand menu.

Click on “Add”.

Enter a name for the link (e.g., VNET1-link).

Select the subscription and virtual network (VNET1).

Enable auto-registration to ensure that VMs are automatically registered in the DNS zone.

Click on “OK”.

Repeat the process for VNET2.

Step 3: Configure DNS Settings for VNET1 and VNET2

Navigate to VNET1 in the Azure Portal.

Select “DNS servers” under the “Settings” section.

Ensure that the DNS server is set to “Default (Azure-provided)”.

Repeat the process for VNET2.

Step 4: Verify Name Resolution

Deploy a virtual machine in VNET1 and another in VNET2.

Connect to the virtual machines using Remote Desktop Protocol (RDP) or Secure Shell (SSH).

Test name resolution by pinging the VM in VNET2 from the VM in VNET1 using its hostname (e.g., ping .contoso.azure).

Explanation

Private DNS Zone: This allows you to manage and resolve domain names in a private network without exposing them to the public internet.

Virtual Network Links: Linking VNET1 and VNET2 to the DNS zone ensures that VMs in these networks can register their DNS records automatically.

Auto-registration: This feature automatically registers the DNS records of VMs in the linked virtual networks, simplifying management.

DNS Settings: Using Azure-provided DNS ensures that the VMs can resolve each other’s names without additional configuration.

By following these steps, you ensure that virtual machines on VNET1 and VNET2 are included automatically in the DNS zone contoso.azure and can resolve each other’s names seamlessly.

There is no virtual network peering between VM4’s VNet (VNet3) and VM5’s VNet (VNet4). To enable the VMs to communicate over the Microsoft backbone network a VNet peering is required between VNet3 and VNet4.

No

subnet1(WM1->NSG1 outbound->NSG10 outbound)->subnet2(NSG1 inbound->NSG11 inbound->VM2)

Yes

NSG10 blocks ICMP from VNet4 (source 10.10.0.0/16) but it is not blocked from VM2ג€™s subnet (VNet1/Subnet2).

No

NSG11 blocks RDP (port TCP 3389) destined for ג€˜VirtualNetworkג€™. VirtualNetwork is a service tag and means the address space of the virtual network (VNet1) which in this case is 10.1.0.0/16. Therefore, RDP traffic from subnet2 to anywhere else in VNet1 is blocked.

Box 1: VM2, VM3 and VM4.

VM1 is in VNet1/Subnet1. VNet1 is peered with VNet2 and VNet3.

There are no NSGs blocking outbound ICMP from VNet1. There are no NSGs blocking inbound ICMP to VNet1/Subnet2, VNet2 or VNet3. Therefore, VM1 can ping VM2 in VNet1/Subnet2, VM3 in VNet2 and VM4 in VNet3.

Box 2:

VM4 is in VNet3. VNet3 is peered with VNet1 and VNet2. There are no NSGs blocking outbound ICMP from VNet3. There are no NSGs blocking inbound ICMP to VNet1/Subnet1, VNet1/Subnet2 or VNet2 from VNet3 (NSG10 blocks inbound ICMP from VNet4 but not from VNet3). Therefore, VM4 can ping VM1 in VNet1/Subnet1, VM2 in VNet1/Subnet2 and VM3 in VNet2.

NGS1 only

VM2, VM3, VM4 and VM5

Box 1: No

Zone2.contoso.com is not linked to any virtual networks. Therefore, no VMs are able to resolve names in the zone.

Box 2: Yes

VM4 is in VNet3. Zone1.contoso.com has a link to VNet3 and auto-registration is enabled on the link.

Box3: No

VNet3 is linked to zone1.contoso.com and auto-registration is enabled on the link. A virtual network can only have one registration zone. You can link zone2.contoso.com to VNet3 but you won’t be able to enable auto-registration on the link.

Box 1: No

VM1 is in Zone2 whereas the NAT Gateway is in Zone1. The VM would need to be in the same zone as the NAT Gateway to be able to use it. Therefore, VM1 cannot use the NAT gateway.

Box 2: Yes

NATgateway1 is configured in the settings for Subnet2.

Box 3: No

The NAT gateway does not have a single public IP address, it has an IP prefix which means more than one IP address. The VMs the use the NAT Gateway can use different public IP addresses contained within the IP prefix.

VNet 1 will get the default from BGP and propagate it to VNET 2 and 3

For the first question, only ExpressRoute GW SKU Ultra Performance support FastPath feature.

For the second question, vnet1 will connect to ExpressRoute gw, once Vnet1 peers with Vnet2, the traffic from on-premise network will bypass GW and Vnet1, directly goes to Vnet2, while this feature is under public preview.

====Reference

ExpressRoute virtual network gateway is designed to exchange network routes and route network traffic. FastPath is designed to improve the data path performance between your on-premises network and your virtual network. When enabled, FastPath sends network traffic directly to virtual machines in the virtual network, bypassing the gateway.

To configure FastPath, the virtual network gateway must be either:

Ultra Performance

ErGw3AZ

VNet Peering - FastPath will send traffic directly to any VM deployed in a virtual network peered to the one connected to ExpressRoute, bypassing the ExpressRoute virtual network gateway.

https://docs.microsoft.com/en-us/azure/expressroute/about-fastpath

Gateway SKU

https://docs.microsoft.com/en-us/azure/expressroute/expressroute-about-virtual-network-gateways

Box 2: One NSG

The minimum requirement is one NSG. You could attach the NSG to VMScaleSet1 and restrict outbound traffic, or you could attach the NSG to VMScaleSet2 and restrict inbound traffic. Either way you would need two custom NSG rules.

Box 1: Two custom rules

With the NSG attached to VMScaleSet2, you would need to create a custom rule blocking all traffic from VMScaleSet1. Then you would need to create another custom rule with a higher priority than the first rule that allows traffic on port 443.

The default rules in the NSG will allow all other traffic to VMScaleSet2.