Question

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
    {

    }

Answer 1

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