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I am trying to setup the network for a small business using a network configuration I am new to. The business has one public IP(135.x.x.x) and wants to use separate machines for its website ( on and sharepoint site ( on The DC is on

I have added DNS Host A records for the sites pointing to the private IP address of the hosting machine. From inside the LAN, all users can access the web and sharepoint sites. But from an external PC, the websites return a 401 error.

Not sure whether my problem is topology, DNS, firewalls, or if the concept is simply not possible with only one public IP.

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How is external traffic getting to the websites? Is this internal or external DNS where you've specified the internal number? – Katherine Villyard Oct 4 '13 at 19:37
Please don't cross-post...… – Zoredache Oct 4 '13 at 20:03
If possible, get a second public IP, and do 1-to-1 forwarding for both sites on the firewall. – DanBig Oct 4 '13 at 20:06
up vote 3 down vote accepted

If you want to access the site publicly, you must use the public IP address, and the firewall must allow that port through to your private web server. If you wish to use Sharepoint as well, which (IIRC) runs on the same port as a web server, you must have a second public IP or you must force the clients to specify a different port number (e.g. (not a valid URL) )

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This may lead to issues with your internal machines not being able to get to the resources required unless you're careful with how you NAT the addresses on the firewall, so please take the time to read up on your firewall thoroughly before trying to implement. – John Oct 4 '13 at 19:38
What he said. You could port forward through your firewall, perhaps, but you'll need to put one or other server on a nonstandard port. – Katherine Villyard Oct 4 '13 at 19:53
Or the OP could use a proxy to direct the traffic appropriately. – joeqwerty Oct 4 '13 at 20:37
@John Thanks. Although the machines have individual IP addresses, it hadn't clicked that they were all still using the same public IP:Port combination. Port forwarding meant that only one of the private IPs could ever serve a site on HTTP(80). The problem was resolved by assigning unique ports and forwarding those to the respective private IP address. – wwirthtorres Oct 5 '13 at 17:30

I Did something similar with a corporate Intranet, and a Zimbra Mail server. I setup Apache with name based virtual hosts, and used mod_proxy present the sites residing on different web servers. This way, you can have pointing at the company website, and pointing at sharepoint. Both would be accessed on port 80 or 443 as required.

mod_proxy documentation is here:

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