当您使用 IE 打开 FTP 站点,并使用 ISA 作为 web 代理(并且没有勾选 IE 高级选项”Enable folder view for FTP sites”),访问需要认证的 FTP 站点时, ISA 服务器可能会返回以下报错:
Error Code: 502 Proxy Error.
The login request was denied. The logon account might have been disabled or logon information might have changed. Log on again to verify that the information was typed correctly. If the problem continues, report the problem to the administrator of the Internet server you are requesting.(12015)
参考
Error message when a client computer tries to access an FTP site through ISA Server, Microsoft Forefront Threat Management Gateway, Medium Business Edition, or Windows Essential Business Server 2008: "Error Code: 502 Proxy Error"
http://support.microsoft.com/kb/925880/en-us