Hi, welcome to the forums

Ok, network connectivity... To be honest I've never really made anything networked myself, so I'm not going to be much help, but I'll try to help

DBPro does have built-in network commands that use the DirectPlay API, but it's probably best not to go using them... DirectPlay is an outdated system, and in my experience the build in commands can be very buggy. Try downloading one of the free network plugins (The two I know of are Tempest and Multisync), and having a play around with the commands in that.
Good luck, post again if you get stuck :3