Network drive encryption mac question?

[jamini.roy900]

So in one of my desktops i have a hard drive that i am using as a network drive, the computer has encryption, the accounts do, but when i connect to it on my mac i can type in the wrong username/or password/network, and it will still let me connect. Should i be concerned about someone getting into this information? Also i tried to lock the important files from my mac computer but it would not stay locked. Can someone tell me how to lock the files on a windows/mac, and if this is safe?