Lost Network Some Network Connections

This is possible, but..

What about the network logical structure of the two buildings?
Are they on separate vlans? Are switches layer 3?

They are on the same vlan. The switches are Cisco Catalyst 1950.

You shuld check at the running-config (if for example they didn't a write mem). Check on the ports configuration.

I would restore a saved configuration with
'backup ....
copy running-config tftp://<hostname>/BKPCFG

'restore from a previously saved config file. (PAY ATTENTION: THIS WILL REBOOT THE SWITCH)
copy tftp://<hostname>/<filename> startup-config
reload

Otherwise you can start thinking about the port damage...
 But what about the network link? it is UP?
try a "show interface <number>" on a interface that is giving the problem. post the result.

Network link is up. About half the systems work. In fact, the entire computer lab is connecting it is the classroom computers that are not getting any connection. They all run from the same switch.

If you ask CISCO for RMA (assumed you have proper surge protection, UPS and switches went down due to a prolonged power outage) they'll surely ask you to try restore a previos backed-up configuration and perhaps to try update the IOS (if you have access to the downloads).


I would try to restore it anyway. At least, try to compare running cfg and backed up with winmerge...

Here's the problem - I have no idea if there is a backup of the configuration anywhere. This network was setup long before the current principal or I came on the scene. There was virtually no information left for us and I would know where to begin to look.

Oh... WOW.

you don't really have any idea of who setup the net initially (external people)? Service provider often keeps backups of their cfg...

I would be looking for an interim switch that deals with the classroom.
Because its a classroom (now) I find it easy to imagine that it wasn't hard wired computer-for-computer back to the Cisco switch.

24-port Cisco
How many classroom computers?
Do they *really* each have their own port on the Cisco?
If you look at the Cisco control panel, what does the dynamic MAC address table tell you about devices and port connections?

Upon further investigation I found that 1) I need to make a really good map of our network; 2) it is not at all as it was described to me.
I was able to access to switch cabinet today for the first time. Had a maintenance guy who had possession of the keys because there is phone equipment located in the same cabinet and he was reluctant to allow others to have access. When I got in the cabinet I found three switches. Evidently this network was originally setup with two Cisco Catalyst 1900 24 port switches. One of these switches, at some point, failed. It was replaced with a Dell Power Connect 2024. It is the Dell that failed this time. There was no power to the Dell and I could not get it to power up at all. I am suspecting a possible surge that caused this problem.
Every classroom has at least 2 Ethernet connections and there are cables run from the classrooms to the patch panels in the switch cabinet. I do have a temporary work around that will allow me to get at least one system in each classroom connected while we decide what the permanent solution will be.

Great troubleshooting fmarshall! :-)