Forum OpenACS Development: Re: can't connect to openacs.org port 80: network is unreachable
The cause was IPv6 being enabled, while the hardware of the server provides no support to it. Thus, every time ns_http tried to use IPv6, it returned a colateral error (i.e. network in unreachable).
We've have disabled IPv6, and now ns_http runs only on IPv4 only and the page "/admin/install" loads successfully.