[Koha] Apache default page

[Lawrence Bean]

Hello folks. I'm brand new, and just successfully finished setting up KoHa
on a Macintosh running 10.4 Tiger. When at the koha computer, I open a web
page and type
http://localhost
and up pops the opac main page just like it should.

However, accessing from a remote machine with
http://172.16.1.11
brings up the Apache default page.

To test locally, I went to the koha machine and double-checked the IP
address, which is correctly 172.16.1.11, then tried 
http://172.16.1.11
right at the koha machine, and up came the Apache default page.

Switching to the loopback IP, though,
http://127.0.0.1
brings up KoHa.

I even tried:
http://172.16.1.11/cgi-bin/koha/opac-main.pl
at the koha machine and got the "Not Found" response.


So, it seems there is a setting in Apache that I missed. Any help, or
pointing me in the right direction to help myself, would be greatly
appreciated.