I used a work computer to post a comment that someone is trying to track with the help of a lawyer. Under subpoena, the site gave up the IP address that was active during the time I made the post. The ISP can now trace the IP to my employer. I used a computer that is wired to the network. Will the IP lead directly to that terminal? Or would it be inconclusive because there are hundreds of wired terminals on the network and my employer also offers public wifi? I'm wondering if the IP address can be traced all the way back to the specific terminal I used to post the comment, or if the trail will only go as far as the building the computer was in.
The public IP will lead them to your company's network. Your company's network administrator may then be able to look at their logs to determine which computer inside the network initiated that outbound traffic. In general, you should always assume your employer knows everything you are doing on their network.
There are also additional ways to identify you other than by IP. Depending on how ill-advised of an action you took, these may or may not come into play (posting an abusive comment, probably not; accessing child porn, certainly).