The sample code shown in the PHP manual is one way to get the server name without requiring a new variable to be defined in base_conf.php.
  $host  = $_SERVER['HTTP_HOST'];

From: Kevin Johnson []
Sent: Sunday, July 30, 2006 5:24 PM
To: Briggs, Bruce
Cc: BASE Developers
Subject: Re: [Secureideas-base-devel] Use Archive Database Doesn't Work

On Jul 28, 2006, at 9:47 AM, Briggs, Bruce wrote:

In the PHP manual:
"Note: HTTP/1.1 requires an absolute URI as argument to Location: including the scheme, hostname and absolute path, but some clients accept relative URIs."
The  header statements in base.main.php use a relative URI, not an absolute URI.
When I change the relative URI to an absolute one, things now work on IIS 6.0.
I think that all  header("Location:  code lines should be changed to absolute URIs.

Makes sense... Good catch.  Does anyone see a reason why we couldn't just change the instructions for the base_conf.php to have them enter a server name also?
This would make the URL absolute.