Depends on how your administrator set up the rules and how sneaky (experienced!) You are. There is a good chance that you have locked your IP address only for the connection via port 80-out (lazy administrator). Therefore, there are several alternatives available, e.g. For example, using a proxy on another port or connecting remotely to another PC or server. However, you'll need to research a bit to see if you can figure out what kind of rules you've used. Success depends on what type of monitoring the administrator has set up and whether you would do so easily.
If you have physical access to a PC or server on the network that has Internet access, this is relatively easy, depending on whether the BIOS is password-protected (usually easy to bypass) and whether you are using the PC / server via USB can start. CD or DVD, but now you are able to do something illegal just to access the internet.
There may be ways to do this at the end of the day, but all will make you lose your job if caught.
As I said earlier, it is better if you are at work and be warned that if you find a way out, you are likely to lose your job.