The IP address 172.18.3.1 : Class B networks
Secure IP address This IP is only local, it is not accessible from outside the network
Rating: 5
This means that the IP address is not accessible from the Internet, it is local and only accessible within the network. Everyone has the same local address (172.16.0.0 - 172.31.255.255).
Each device (laptop, printer, scanner, phone, surveillance camera, tablet, ...) has a unique local IP address assigned by the adsl box that allows the box to identify the different devices to within a local network and send the right product at the right flow.
Specifically, the adsl box has a public IP address in your case, which connects to the Internet and the box assigns a local address to all devices to identify them.
The IP address 172.18.3.1 detail
The IP address 172.18.3.1 (IPv4 Class B networks) belonging to the network 172.16.0.0 - 172.31.255.255 is written in long version -1408105727.
Color obtained mathematically from the IP address: Darkish red
Addresses on the same network : 172.18.3.0 172.18.3.2 172.18.3.3 172.18.3.4 172.18.3.5 172.18.3.6 172.18.3.7 172.18.3.8 172.18.3.9 172.18.3.10 172.18.3.20 172.18.3.30 172.18.3.40 172.18.3.50 172.18.3.60 172.18.3.70 172.18.3.80 172.18.3.90 172.18.3.100 172.18.3.200 172.18.3.254 172.18.3.255