ASP.NET擷取IP的6種方法

服務端：

//方法一
HttpContext.Current.Request.UserHostAddress; 

//方法二
HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

//方法三
string strHostName = System.Net.Dns.GetHostName();
string clientIPAddress = System.Net.Dns.GetHostAddresses(strHostName).GetValue(0).ToString();

//方法四（無視代理）
HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
           

用戶端：

//方法五
var ip = '<!--#echo var="REMOTE_ADDR"-->';
alert("Your IP address is "+ip);

//方法六（無視代理）
function GetLocalIPAddress() 
{ 
    var obj = null; 
    var rslt = ""; 
    try 
    { 
        obj = new ActiveXObject("rcbdyctl.Setting"); 
        rslt = obj.GetIPAddress; 
        obj = null; 
    } 
    catch(e) 
    { 
        // 
    } 
     
    return rslt; 
} 
           

來自印度的MCT Maulik Patel提供了一種服務端的解決方案，很好：

if(Context.Request.ServerVariables["HTTP_VIA"]!=null) // using proxy
{ 
     ip=Context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();  // Return real client IP.
}
else// not using proxy or can't get the Client IP
{ 
     ip=Context.Request.ServerVariables["REMOTE_ADDR"].ToString(); //While it can't get the Client IP, it will return proxy IP.
}