I setup a server dedicated to running Web and FTP for our company. I opened up ports 21 and 80 on our router and used a webbased tool to verify the ports are open. I then closed the ports on the router and verified if it would update as closed, which it did. So my settings on the router are correct.

On any local machine, I can type in the local IP of the website and see the default IIS page. However, I can't access it using the public IP. I tried accessing from an outside network, a mobile smartphone, etc. I opened up port 80 and 21 on the server's firewall. Still nothing.

Any idea on what I need to check/configure to get this to work?


Ensure that you forwarded port 80 and port 21 on your router to the IP address of the server.

  • I already had forwarded to the local IP of the server – Markaway Dec 19 '12 at 19:41

Check the firewall on your local machine.

  • Why would my local machine block the public IP and not the local IP? If i'm able to browse the server locally, and other web sites like Google fine, I can't see how anything on the local machine would affect this? – Markaway Dec 19 '12 at 19:23
  • Your term "On any local machine" leads me to believe that you were talking about anything running locally on the host itself. So there is a SITE LOCAL IP and a different OUTSIDE IP number? You'll need to describe your network architecture if this is the case. – mdpc Dec 19 '12 at 19:26
  • The server running IIS is, my local machine or workstation is Both of them can access the default IIS page by going to However, the public IP given by my ISP, does not work. I verified the ports are open/forwarding on the modem and router. The server has ports 80 and 21 open. – Markaway Dec 19 '12 at 19:28
  • BTW, This type of information should be put in the original note as it is of significant import in helping you to solve your problem. It sounds like the routing between the external IP is not being correctly routed/translated to your internal address. – mdpc Dec 19 '12 at 19:30

It depends on the make/model of your router, but usually you need to add a NAT rule to allow internal LAN machines to access the local server by its public IP.

NAT the internal source IP to the public IP and things should work.

  • Netgear UTM25. Not sure how to set this NAT up – Markaway Dec 19 '12 at 19:58

If the IIS runs on WIN2008 or higher then check the local windows firewall. BTW, for FTP there is also port 20 required.

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