Why do I always get the same IP when getting Request.UserHostAddress in WebAPI custom action filter?

Question

I've created a Web API custom action filter to log incoming calls. I'm trying to get the caller's IP address and everything I've found says to use Request.UserHostAddress. The problem is that no matter where the call is coming from, the IP is the same.

Here's the code for my action filter:

public class LogActionFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        var name = actionContext.ActionDescriptor.ActionName;

        // Get the sender address
        var caller = ((HttpContextWrapper)actionContext.Request.Properties["MS_HttpContext"]).Request.UserHostAddress;

        // Log the call
        SystemBL.InsertSiteLog("WebAPI:" + name, "From:" + caller);
    }
}

I've also tried with:

var caller = ((HttpContextWrapper)actionContext.Request.Properties["MS_HttpContext"]).Request.ServerVariables["REMOTE_ADDR"].ToString();

but the result was the same. Any ideas?

Answer 1

Found the answer here: HttpContext.Current.Request.UserHostAddress is null.

Basically, I needed to sort out the forwarding. The final code is:

    public override void OnActionExecuting(HttpActionContext actionContext)
    {
        var name = actionContext.ActionDescriptor.ActionName;

        // Get the sender address
        var myRequest = ((HttpContextWrapper)actionContext.Request.Properties["MS_HttpContext"]).Request;
        var ip = myRequest.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if (!string.IsNullOrEmpty(ip))
        {
            string[] ipRange = ip.Split(',');
            int le = ipRange.Length - 1;
            string trueIP = ipRange[le];
        }
        else
        {
            ip = myRequest.ServerVariables["REMOTE_ADDR"];
        }

        // Log the call
        SystemBL.InsertSiteLog("WebAPI:" + name, "From:" + ip);
    }

Thanks everyone. I'll mark it as the answer in 2 days when it lets me.