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Zorluk: KolayConfigure User-Defined Routes and Routing Tables

An administrator creates a new Azure virtual network named `VNet-Main` containing a subnet named `Subnet-Web` (192.168.10.0/24192.168.10.0/24) and a subnet named `Subnet-Security` (192.168.20.0/24192.168.20.0/24). A custom firewall VM is installed in `Subnet-Security` at 192.168.20.10192.168.20.10. By default, system routes allow direct subnet-to-subnet communication and direct outbound internet access. You need to ensure that all outbound internet traffic from `Subnet-Web` is redirected through the custom firewall VM instead of going directly to the internet. Which two actions are required to achieve this goal? (Select two.)

  1. Enable IP forwarding on the Azure network interface (NIC) of the custom firewall VM.Cevap
  2. Create a route table containing a 0.0.0.0/00.0.0.0/0 route that specifies 192.168.20.10192.168.20.10 as the next hop address, and link this table to `Subnet-Web`.Cevap
  3. C
    Create a route table containing a 0.0.0.0/00.0.0.0/0 route that specifies 192.168.20.10192.168.20.10 as the next hop address, and link this table to `Subnet-Security`.
  4. D
    Enable IP forwarding on the Azure network interfaces (NICs) of all VMs in `Subnet-Web`.

Cevap

Enable IP forwarding on the Azure network interface (NIC) of the custom firewall VM, and create a route table containing a 0.0.0.0/00.0.0.0/0 route that specifies 192.168.20.10192.168.20.10 as the next hop address, and link this table to `Subnet-Web`.
To route outbound traffic from the web subnet through a custom firewall, you must create a route table with a default route (0.0.0.0/00.0.0.0/0) pointing to the firewall's private IP address (192.168.20.10192.168.20.10) and associate it with the web subnet. This user-defined route overrides the default system route to the Internet. Additionally, because the firewall VM is acting as a router/transit device, you must enable IP forwarding on its Azure network interface so Azure does not drop transit packets.

Adım Adım Çözüm

1
Configure the Network Virtual Appliance (NVA) capability by enabling IP forwarding on the custom firewall VM's network interface in Azure.
The firewall VM is permitted to receive and forward network transit traffic not addressed to itself.
By default, Azure drops traffic sent to a virtual machine if the destination IP does not match the VM's network interface IP.
2
Create a custom route table, add a route for the default destination (0.0.0.0/00.0.0.0/0) pointing to the private IP of the firewall (192.168.20.10192.168.20.10) as the next hop, and associate this route table with `Subnet-Web`.
The custom User-Defined Route (UDR) overrides the default system route for internet traffic (0.0.0.0/00.0.0.0/0 -> Internet) for all hosts in `Subnet-Web`.
User-Defined Routes have a higher precedence than default system routes, allowing administrators to redirect outbound traffic.

Anahtar Kavram

User-defined routing precedence and network virtual appliance transit configuration
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