Microsoft Philippines Community

I tried the following approach:

using System;
using System.Web;

public partial class WhatsMyIP : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        tbIPs.Text += "HttpContext.Current.Request.UserHostAddress:" + Environment.NewLine +
                      HttpContext.Current.Request.UserHostAddress + Environment.NewLine + Environment.NewLine;
        tbIPs.Text += "HttpContext.Current.Request.ServerVariables['REMOTE_ADDR']:" + Environment.NewLine + HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"] + Environment.NewLine;
        tbIPs.Text += "System.Net.Dns.GetHostName():" + Environment.NewLine + System.Net.Dns.GetHostName() + Environment.NewLine;
        tbIPs.Text += "System.Net.Dns.GetHostAddresses(System.Net.Dns.GetHostName()).GetValue(0).ToString():" +
                      Environment.NewLine +
                      System.Net.Dns.GetHostAddresses(System.Net.Dns.GetHostName()).GetValue(0).ToString() + Environment.NewLine;
    }
}

but it seems to failed, when test it on actual server which is under an ISA/Firewall.


I have gone thru couple of forums such as:

Possible solution, BUT we need to use Active X (which is not a good approach).
Source: http://forums.asp.net/p/1276422/2432905.aspx#2432905
Q: How can I use JS to detect client IP?
A: You can get the actual IP by JavaScript, with the help of an ActiveX control, but the presents possibilities is low, because many browsers avoid ActiveX control and plug-in. see the source link for more details.

Possible solution:
See : http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/ASP_DOT_NET/Q_21509072.html
Q: Retrieving a clients IP address
A: EugeneK-biruza: Anyway, reconfiguring the firewall to force it pass original address in additional headers will be the 100% working solution.

Can someone point me on how to "reconfiguring the firewall to force it pass original address in additional headers" , where using ISA as firewall.

Thanks in advanced.

Hmm ... if one is able to do this across NAT, then that would invalidate NAT, right? Besides, what you will get would be private IP addresses, which are inaccessible in the Internet. I mean, imagine your results would be 192.168.x.x or 10.x.x.x, useless.

Tama ba?

I think if you pass thru ISA or other proxy servers it'll tack on a "X-Forwarded-For:" header which will contain the original IP of the browser that made the request. It's just a header though, and it can be forged so it isn't a very reliable means of identification.

Can someone help me on this, esp. on seting up the ISA server

Have you tried this:

public string IpAddress()
{
    string strIpAddress;
    strIpAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
    if (strIpAddress == null)
    {
       strIpAddress = Request.ServerVariables["REMOTE_ADDR"];
    }
    return strIpAddress;
}

 

I did, it returns SERVER address, not the client.

dapat ang kunin mo e yung exposed IP (public IP), not the NAT IP. 

I encountered that problem before when I developed a web app using single singon and published outside. My concept is the web app get first the IP of the client machine, but we are behind ISA, in this case when user try to browse the web outside our network the result of the REMOTE_ADDR ip is the IP address of the ISA (according to our back office guys this is normal since are network is behind ISA). But when the IP is not equal to the IP addr of the ISA or the first 3 numbers is equal to our company ip (ex: 192.168.1.xx) then I am assuming that the user is on our network.

To make things complicated, things might turn out to be this...

Company Internal Network (NAT) <-> (private)ISA(Public to ISP) <-> ISP Network (NAT) <-> (Private to ISP) Gateway (Public to the world)