用firefox访问非常规port的网页

今天为装zuccaro，随便选择了一个端口6000，用IE和Opera访问都没有问题，但是没想到用firefox访问时却得到提示：

This address is restricted      

This address uses a network port which is normally used for purposes other than Web browsing. Firefox has canceled the request for your protection.

后来在google上找到了解决办法：
The only way to fix this problem is to add a new variable to Firefox's configuration.
You do this by:

1. Entering about:config in the URL bar.
2. Right click the list that is displayed and choose New->String
3. Enter network.security.ports.banned.override as the name of the new string and click ok.
4. Enter the ports you want allowed, seperated by commas (like: "101,800,5000"). Click OK.