I have tested a build on 3 different OS X machines and 1 Ubuntu. The ports are configured correctly and I verified using docker ps & docker inspect yet it looks like docker isn't opening the ports in OS X because netstat doesn't list the docker ports
netstat -an | grep 'LISTEN'
Our devs use OS X, I was fortunate that one of the devops has an Ubuntu machine. I don't have any funky proxy settings blocking it.