IIS/firewall problem


I have set up a web site which runs off one of our internal web servers. Everything works fine when I try to access the site from within our network but unfortunately it doesn't work at all when I try to access it over the internet - I get "Cannot find server" error page.

I have configured NAT so that one of our external IP addresses points to the internal IP address of the server - I know this is working because I have accessed other services on that server externally. I have also purchased a domain name and have configured its A record to point to the server's external IP address. I have configured the host header name in IIS to the domain name.

I have also opened port 80 on our firewall so that it is open for the source as the internal LAN web server IP and the destination as "*".

I'm almost totally sure it's a firewall issue because:

1) It works fine internally within our network 2) It still doesn't work when I add the domain name and external IP to my Hosts file (therefore it won't be a domain issue)

Does anyone have any suggestions as to what the problem could be? Do I only have to open port 80 for IIS?


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Port 80 is all you need for HTTP traffic, and 443 if you use SSL, I think your firewall is still the problem. I would check the firewall logs and see what you find there.

Reply to
Chris Crowe [MVP]

Sounds good.

Hm... did you think about the classical three zone concept? Perhaps, it would be a good idea to have this web-server in a DMZ.

You only have to open port 80 usually - if you're not offering web on another port. It's difficult to make a diagnosis from here, though.

Yours, VB.

Reply to
Volker Birk

Shoudnt that be the other way around? source as "*", destination as internal LAN web server IP?

But also note the firewall might not see the destination as internal LAN web server IP because of the NAT. Trying allowing port 80 traffic in to the external IP from anywhere.

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