Adding networks: Technical details

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Reverse DNS zones will be created automatically while adding a network. Reverse zone may have the maximum allowed size, however it must be less than or equal to the network size.

For IPv4 networks - /8 /16 /24. If trying to create a network, which is less than /24, depending on DNS server settings a /24 network, or classless reverse zone which size equals to the network being created, will be added.

For IPv6 - /12, /16, /20, /24, /28, /32, /48, /64. Please note: creating networks of other size will increase the number of reverse zones. For example, when you are creating a /47 network, two /48 reverse zones will be added. When you are creating a /49 network, 32768 /64 reverse zones will be added. Such a great number of zones may result in low efficiency, besides some zones may not be created (they will be created when trying to access them for the first time). If you are creating networks, which are less than /64, a /64 zone will be added. All of the zones created within /64 will be handled by this zone.

Reverse zones are created with parameters specified in the DNS server settings module

If a reverse zone is not present in DNS for the specific gateway, the IP will be considered already in use and won't be allocated to clients. Special IP addresses from this network are also marked in use.

As a result, you will get the network with 3 IP addresses, which are already in use.