public void updateProxy(boolean enabled,String server, int port, String username, String password) throws SecurityException {
checkWriteAccess();
boolean hasAccess=ConfigWebUtil.hasAccess(config,SecurityManager.TYPE_SETTING);
if(!hasAccess) throw new SecurityException("no access to update listener type");
Element proxy=_getRootElement("proxy");
proxy.setAttribute("enabled",Caster.toString(enabled));
if(!StringUtil.isEmpty(server)) proxy.setAttribute("server",server);
if(port>0) proxy.setAttribute("port",Caster.toString(port));