Internet Explorer works with the plug-in but it also needs to load:
LoginProConnection.exe - UDP 53/22223/7001/7002 (22223 is probably the control port so might change)
cac.exe - UDP 53 - TCP 443
No other browser prompted for these connections but even with these rules in the firewall, no other browser will connect using the plug-in. Chromium and Dragon will connect over HTML, firefox won’t connect at all.