Because you have a DHCP server in the network.
A portion of a network that shares a common address component. On TCP/IP networks, subnets are defined as all devices whose IP addresses have the same prefix. For example, all devices with IP addresses that start with 100.100.100. would be part of the same subnet. Dividing a network into subnets is useful for both security and performance reasons. IP networks are divided using a subnet mask.
DHCP Dynamic Host Configuration Protocal
Depends on the subnet. For the subnet of 192.168.1.0, the first usable IP address is 192.168.1.1. This is typical of a default wireless router setup. Valid usable IP addresses under this scenario is 192.168.1.1 to 192.168.1.254.
255.255.255.0
The default subnet mask has a standard size. The custom subnet mask allows you to make subnets that are smaller or larger than the default.
The IP address 172.30.0.0 is a private IP address in the Class B range, which has a default subnet mask of 255.255.0.0 (or /16). If you use the default mask, you can create 65,536 addresses (2^16), allowing for 65,534 usable hosts per subnet (subtracting 2 for the network and broadcast addresses). If you further subnet this address, the number of subnets and hosts per subnet will depend on the subnet mask you choose. For example, using a /24 subnet mask would give you 256 subnets with 254 usable hosts in each.
255.0.0.0 for a class A correct. but why? well, 10.10.0.0 is a class a network and all class "a" networks use a default subnet mask of 255.0.0.0. the range of class "a" networks is 1-126.
The default subnet would be 255.0.0.0 (class A)
When forwarding packets to a host on a different subnet, the local host uses the address of the default gateway, which is typically a router within the same subnet. The default gateway serves as an intermediary that routes traffic from the local subnet to other subnets. This address is configured in the network settings of the local host. Packets destined for outside the local subnet are sent to this default gateway for further routing.
ip addresses from 172.16.0.0 thru 172.31.255.255 are private and do not route on the internet.
If this is a default subnet mask, then it would be a class C subnet mask. If you are subnetting a network and this is not the default subnet mask, then it could be either a class A or class B.
255.0.0.0The default subnet mask of a class A network is 255.0.0.0