留言后可以显示留言者的ip
lblID.Text = Request.UserHostAddress;这个是得到用户IP地址的方法
http://www.cnblogs.com/kangtr/archive/2007/09/21/901046.html
http://www.cnblogs.com/itzsl/archive/2009/01/12/1374012.html
简单的就Request.UserHostAddress