This one is very simple: if the subnet mask specified on the host does not match the subnet mask for the network, then communicating with the network will not be possible. Finding the subnet mask is usually quite easy. In recent versions of Windows, such information can be obtained by navigating to Settings | Network Connections, right-clicking on the network adapter you are using, and selecting Properties. There should be a list box displaying the installed protocols; scroll down to internet Protocol Version 6 or Internet Protocol Version 4 depending on what version you are using, and click on the Properties button. This should show you what the subnet mask is.
In Linux, finding the subnet mask is just as easy. ...
