Opera user directory. There you can also turn off that option. Opera has a drop-down list of your History in each window. It is located by clicking on the arrow at the right of the address bar. This will give you your Global History.
Browsers usually goes through a firewall by using a proxy.
Just set up the correct proxies. As yet, Opera does not do that. It's on the list though. My page counter doesn't work with Opera. It shows 888.888.