Is it possible to run ConnectUO behind corporate firewall?

I know it's bad, playing from work, but during my breaks and lunch breaks, would be nice to be able to do this, or while I'm waiting for my carpool person.
I do have server setup (using RunUO), but when I try to connect to my server through connectUO, the UO client launches, and fails at the login attempt. I'm thinking that somehow the corporate firewall is blocking some ports that the UO Client uses?
If not possible, oh well, guess i won't be able to do this during my breaks/lunches