We have a Java application that's accessing a mySQL database via the mm JDBC driver. Our database is listening to the standard port (3306), and is not protected/blocked/filtered by a firewall. However, some of our users are behind corporate firewalls, and they have received SQLExceptions that state "firewall was in the way". Does anyone have any insight as to how to solve this problem - are there solutions other than asking them to open up port 3306 (and is there any other port that they need to open up)? Proxies?? Other ideas?

(My apologies - this may boil down to a driver/basic firewall problem, but I'm hoping someone here has already solved this. . .)