Remote IP address

Question

I have a standalone application which will create connection to another server(pls see codes below):
String stringURL = "http://www.company.com/servlets/TestServlet";
URL url = new URL(stringURL);
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setRequestMethod("POST"); httpCon.setDoOutput(true);
My standalone application is sitting on a machine which is having a fixed IP address.
The funny thing is that the IP address that the connected servlet (TestServlet in this case) get is not the fixed IP address but another one.
Anyone can explain this to me?
Someone tell me that this is because the ISP remaps it somewhere in the gateway or network. If this is true, will the remaped IP address is fixed? or it will changed?
Thanks!

Answer 1

If you are behind a firewall (perhaps in a corporate or ISP network), and you are connecting to a server on the Internet, then the fixed IP that you are using might be hidden by the firewall. Typically, all such requests would appear to the remote server to be coming from the firewall itself. ISP's usually reserve the right to change the IP of the firewall (either because of network restructuring or perhaps failover) but rarely do so.