Exam AZ-700 topic 1 question 25 discussion

Public load balancers allow internet traffic to your VMs by translating their private IP addresses to public IP addresses. You can configure your load balancer with a frontend IP address and load balancer rules to define how incoming traffic is distributed. Azure NAT gateways handle outbound traffic, and only packets arriving as a response to an outbound connection can pass through the NAT gateway. Application gateways operate at layer 7 OSI and can only manage web traffic. Since the question is asking for a solution to ensure Internet traffic can reach the VMs, public load balancer is the way to go. https://learn.microsoft.com/en-us/azure/load-balancer/components https://learn.microsoft.com/en-us/azure/nat-gateway/nat-overview

Inbound to a common public IP requires a public Load Balancer. Outbound using a common public IP requires a NAT gateway. So the answer is D - a public load balancer. Example architecture: https://azure.microsoft.com/en-us/products/application-gateway

B. Azure Application Gateway. "Route traffic to back-end server pools with URL path-based routing, and to MULTIPLE web applications using host header-based routing." https://azure.microsoft.com/en-us/products/application-gateway

Public load balancer

Azure NAT Gateway is a fully managed and highly resilient Network Address Translation (NAT) service. You can use Azure NAT Gateway to let all instances in a private subnet connect outbound to the internet while remaining fully private. Unsolicited inbound connections from the internet aren't permitted through a NAT gateway. Only packets arriving as response packets to an outbound connection can pass through a NAT gateway.

LB can route non HTTP traffic instead of App Gw that HTTP based. Nat Gw handle outbound traffic . Answer is D LB

D is correct, would almost think NAT Gateway but it allows only Internet traffic that is in RESPONSE to traffic originated from Azure vNets i.e. in response ONLY

D seems the best answer, although I have been given to understand that traffic on port 25 is not allowed at all in Azure (because they want you to use Exchange online, obviously)

why not a nat gateway ?

Given answer is correct

Why not Azure Application Gateway with different listeners?

an Azure NAT Gateway is a dedicated network appliance that provides outbound NAT functionality for virtual networks in Azure. It allows resources within a virtual network to access the internet or other resources outside of the virtual network using a single or a pool of public IP addresses.

Given answer is correct