What is the difference between Request.UserHostAddress and Request.ServerVariables["REMOTE_ADDR"].ToString()

Here I can use either of these 2 methods. What are the differences and which one should I use?

Method 1:

    string srUserIp = "";
    try
    {
        srUserIp = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"].ToString();
    }
    catch
    {

    }

Method 2:

    string srUserIp = "";
    try
    {
        srUserIp = Request.UserHostAddress.ToString();
    }
    catch
    {

    }

Short answer: The two are identical.

Long answer: To determine the difference between the two use Reflector (or whatever disassembler you prefer).

The code for the HttpRequest.UserHostAddress property follows:

public string UserHostAddress
{
    get
    {
        if (this._wr != null)
        {
            return this._wr.GetRemoteAddress();
        }
        return null;
    }
}

Note that it returns _wr.GetRemoteAddress(). The _wr variable is an instance of an HttpWorkerRequest object. There are different classes derived from HttpWorkerRequest and which one is used depends on whether you are using IIS 6, IIS 7 or beyond, and some other factors, but all of the ones you would be using in a web application have the same code for GetRemoteAddress(), namely:

public override string GetRemoteAddress()
{
    return this.GetServerVariable("REMOTE_ADDR");
}

As you can see, GetRemoteAddress() simply returns the server variable REMOTE_ADDR.

As far as which one to use, I'd suggest the UserHostAddress property since is doesn't rely on "magic strings."

Happy Programming

There is no difference. They return exactly the same value. However, one is IntelliSense-friendly whereas the other is not.