I configured IIS in my windows 7, and when I enter 'http://localhost' in address bar; I can see my web site. Now, when I want to see my web site by entering internet IP address in address bar, I connect to the ADSL modem (it opens the page which we use to configure the modem!).
It seems that because the modem connects to the internet an gets the IP, not the PC, so the internet IP connects me to the modem. So, I think, I must change some settings of my modem.
I use a D-Link modem.
How can I fix that?
Thanks in advance
Unless you have a "server" or "business" configuration from your ISP which provides you a full subnet of public IP addresses, you've been allocated a single external IP address and the router attached to it does Network Address Translation for all the devices connected behind it. You can confirm this by using ipconfig or Windows Settings (ifconfig on Unix-like machines) to get your IP address. If using NAT, it will start with "10.", "172.16." through "172.31.", or "192.168.". These are "private" addresses and cannot be reached through the public internet.
For someone on the public internet to reach your computer, you need to set up Port Forwarding that redirects incoming traffic on your public, external IP to that port to a machine on the private network. The configuration pages for your router will have this configuration somewhere.
Note that if your router's configuration page is running on port #80 and you really want outside viewers to connect to you without giving an explicit port number, you will probably need to turn off or restrict modem configuration, move it to a another port, or go SSL only (port 443) so as to not cause a conflict with the port you're forwarding.
D-Link is a very common brand of router and there are pages dedicated to configuring port forwarding on them.
Also, just to complicate things, you almost certainly haven't been given a Static IP Address (they are usually quite expensive) which means that your external IP address will change from time to time (perhaps yearly, perhaps daily) making it difficult to tell others how to connect to your page. Your router configuration likely has support for Dynamic DNS (some free, some paid) where the router automatically updates the DNS entry whenever your public IP address changes.