Here's my situation, I have website "A" sitting behind a intranet firewall, inaccessible to the people outside the intranet. I intend to have a outsourced developer work on "A", but he's not able to access it and I can not provide him access to the intranet. So my plan is set up a website "B", that syncs with "A"'s files and database, "B" of course is accessible to the world. My intention is that any changes on "B" would be immediately reflected on "A", likewise any changes on "A" would also be immediately reflected on "B" (a dropbox style sync relationship).
"A" and "B" both are running on linux server, I have root access on "A". I assume "A" would have to initiate the sync always, since "B" can not access "A" from the outside.
Is this possible? if so how would I achieve it?