Exam AZ-700 topic 2 question 62 discussion

"The subnets for IPv6 must be exactly /64 in size. This ensures future compatibility should you decide to enable routing of the subnet to an on-premises network since some routers can only accept /64 IPv6 routes." https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/ipv6-overview#capabilities

Given the requirements, the best recommendation for the subnet mask size would be: B. /120 Here's the reasoning: IPv6 addressing: IPv6 has a much larger address space than IPv4, allowing for more granular subnetting. Subnet size: Each subnet needs to host up to 200 load-balanced virtual machines. /120 subnet mask: In IPv6, a /120 subnet provides 2^8 = 256 addresses. This is more than enough to accommodate 200 virtual machines per subnet while leaving some room for network infrastructure addresses (e.g., gateway). A /120 subnet mask offers the necessary address space while conserving address allocations for other potential subnets or uses within your Azure virtual network.

A /64 subnet mask provides an enormous address space of 2^64 addresses, which is far more than enough to accommodate the required number of virtual machines in each subnet (up to 200). Using a /64 subnet mask aligns with standard IPv6 practices and ensures compatibility with various IPv6 features and functionalities.

Definately A

Definitely answer is A and most people not accepting A as answer is because their mindset is still WIRED to IPv4 IPV6 /64 will take billions of hosts not such 200 vms...you have to remember /64 is IPv6 as IPv4 is max /32 hence both are totally different but same concept, read below for more info Thus routing prefix is /64 and host portion is 64 bits. We can further subnet the network beyond 16 bits of Subnet ID, by borrowing host bits; but it is recommended that 64 bits should always be used for hosts addresses because auto-configuration requires 64 bits. IPv6 subnetting works on the same concept as Variable Length Subnet Masking in IPv4. /48 prefix can be allocated to an organization providing it the benefit of having up to /64 subnet prefixes, which is 65535 sub-networks, each having 264 hosts. A /64 prefix can be assigned to a point-to-point connection where there are only two hosts (or IPv6 enabled devices) on a link.

IPv6-only Virtual Machines or Virtual Machines Scale Sets aren't supported, each NIC must include at least one IPv4 IP configuration. https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/ipv6-overview So in that case its dual-stack, the ipv4 subnet mask for 200 VMs is /24. And Ipv6 subnet mask is /64. But its not clear mask which is asked in the question... assuming it is referring to ipv6 as mentioned initially, answer will be /64

/ 24,Because of the number of host 254. from the question "Each subnet will host up to 200 load-balanced virtual machines."

Chatgpt: /48 subnet mask in IPv6 provides 65,536 subnets, each with a vast address space of 18,446,744,073,709,551,616 addresses. This is more than enough to accommodate your requirement of hosting up to 200 load-balanced virtual machines in each of the 10 virtual subnets, and it allows for future scalability and flexibility in your network design.

/64 The subnets for IPv6 must be exactly /64 in size. This ensures future compatibility should you decide to enable routing of the subnet to an on-premises network since some routers can only accept /64 IPv6 routes. https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/ipv6-overview#capabilities

IPv6 does NOT have /24 --> D is correct --> /64

should be /64