I'm a web developer who makes and maintains websites so I don't have extensive knowledge of networking. I work for a small company that uses a third party hosting service to host our website. One of our clients is a large company that uses Port Address Translation. Unfortunately, when they visit our website it brings up the generic server page that just has the hosting provider's logo and the client's IP address.

Now, no one has ever complained about this before so this is news to me. I've tried to Google the problem, but it doesn't seem to bring up anything related to this issue. Everyone in our office is able to access the website fine. I can access it from home and school with no problem. I called our hosting provider, and they told me they can access the website fine and it must be a problem with our client's PAT configuration.

Our client claims it's the hosting provider that's having issues. Our client's IT guy says that when using a static IP address to connect to the internet (using NAT), then our website comes up fine, but when switched back to PAT it fails.

Now, my question is, who is at fault here? Is it the hosting provider or our client?

1 Answer 1


Sounds like the client site is using something more than just vanilla PAT (probably a proxy or possibly some security/threat-management gateway). Regardless, the host header is likely being stripped out of the request, so your server has no idea what website they're trying to access.

I would imagine this is a common problem for the client, and is something they should fix. You can probably work around it by getting a dedicated IP for your site.

  • +1 - I was just typing up the same ideas about a proxy/gateway and the host headers being stripped
    – Goyuix
    Commented Oct 14, 2010 at 15:03
  • So, the request is being stripped out so that only an IP address is passed? I did a WHOIS on our domain and using the IP address it will bring up the server page I mentioned. Does this mean our website is using a dynamic IP address? Is there anything I can do with the hosting provider besides getting a static IP address?
    – Alex
    Commented Oct 14, 2010 at 15:52
  • @Alex. Yes, the request normally has the IP and www.example.com (so the server knows which website they were trying to get to). The WHOIS will always show whoever owns the IP. The address is static, not dynamic; but it is also shared with several websites. The only option you have is to get a dedicated IP for you site (so it's not shared with other sites). When an IP is shared, there's a default site, which is the page shown on the WhoIs preview, and the page the client is seeing. All other sites are accessible only if the request includes the site, which they normally do.
    – Chris S
    Commented Oct 14, 2010 at 16:52

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