监测项目错误日志时经常会报：

System.Web.HttpException: 客户端已断开连接。 ---> System.Web.UI.ViewStateException: 无效的视图状态。Client IP: 60.29.228.190Port: 62190User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Apache; .NET CLR 1.1.4322; .NET CLR 2.0.50727)ViewState: 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... ---> System.FormatException: Base-64 字符数组的无效长度。

这个项目用的是Form安全验证，经分析可能是由于负责均衡导致的。

解决方案：在页面头部添加 EnableViewStateMac="false" EnableEventValidation="false"