First of all, you need to learn terminology to read
192.168.1.0 is network ID. It refers to your local network, and every interface (this is also important - you can have multiple interfaces on same machine) that connects to that network will have address that start with
192.168.0.xxx.It's not scanning outside of your router, so you're not scanning your ISP (and I recommend that you avoid doing that).
Depending on the configuration of your router, network can contain different number of hosts. If you say
/24 means you have 256 hosts on the network (this is because each IP address when converted to binary will be 32 bits in length, and we can vary last 8 bits, so those first 24 bits are not changing). When you perform scan like that,
nmap also will confirm how many hosts it scanned:
OS detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 256 IP addresses (3 hosts up) scanned in 202.14 seconds
nmap doesn't actually know your network configuration. Use
ip addr to find out which exact CIDR-style addressing to use. For example, I have:
$ ip -4 -o addr show
1: lo inet 127.0.0.1/8 scope host lo\ valid_lft forever preferred_lft forever
3: wlan7 inet 192.168.0.101/24 brd 192.168.0.255 scope global dynamic wlan7\ valid_lft 63435sec preferred_lft 63435sec
Second, you have two examples there. Once ending with
.0 and one ending with
.1xx. As far as
nmap is concerned , it's the same thing. From
For example, 192.168.10.0/24 would scan the 256
hosts between 192.168.10.0 (binary: 11000000 10101000 00001010 00000000) and 192.168.10.255 (binary: 11000000
10101000 00001010 11111111), inclusive. 192.168.10.40/24 would scan exactly the same targets.