Question about networking problems

[Bob Bobbio]

I was wondering if there was a list of network troubleshooting steps if something goes wrong. In case the problem is something simple and you don't have to call a professional to come out evey time just to fix a simple thing and then charge like $200. Because the network we have has a problem and a professional is already schedualed to come. You see on the network all the Windows and OS X machines stopped getting iternet all of a sudden. The local area network works fine except on the OS X. All the Mac OS 9 computers get internet tough. It all happened suddenly for no apparent reason. Then there are some Windows computers on another router that is connecter to a line from the main router and they work fine, so it is very perplexing indeed. Asuming that you read this message in order I thank you for reading this message and that maybe you could lend some help for the future in case such a problem could arise again. Thank you sincerly.

 

[Ethereal_Dragon]

How large is this network?
&nbsp&nbsp&nbsp&nbsp&nbsp # of Hosts?
&nbsp&nbsp&nbsp&nbsp&nbsp # of Routers?
&nbsp&nbsp&nbsp&nbsp&nbsp # of subnets?
&nbsp&nbsp&nbsp&nbsp&nbsp Describe Topology of the network
&nbsp&nbsp&nbsp&nbsp&nbsp Do all of the PC's that lost conectivity share a common router, or a common subnet?

 

[Bob Bobbio]

We got one of the computers working by changing the IP address to a specific one then letting the router assign it one, and now there is only one computer that doesn't get internet, and the strange thing is that it also doesn't get the local area network, We think it's a hardware thing.
The problem I guess was that the router decided not to give the computers an address. Thank you. I really would like to know where on the internet I can learn about this stuff please. So such problems I can fix.