IMHO, the best way to get at that information is through CGI.pm's method virtual_host():

use CGI;

my $cgi = CGI->new;

my $domain = $cgi->virtual_host;
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It will attempt to Do The Right Thing in determing the virtual host's name. I believe it is cleaner, and more portable to use CGI's methods to access the CGI specific environment variables, than to access them directly by hand.

In reality, all that's going to do is give you $ENV{"HTTP_HOST"} (or $ENV{"SERVER_NAME"} in the highly unlikely event of the Host: request header being specified)

The Host header (read $ENV{"HTTP_HOST"}) which is manditory for HTTP/1.1 (and IIRC also for HTTP/1.0) specifies the host name for the request; this was designed specifically for "virtual hosting".

If you already have a CGI object floating about, then I'd recommend using $cgi->virtual_host. If you don't, it's probably easier to just use $ENV{"HTTP_HOST"}

--
RatArsed

Perhaps something has changed in all these years: using PERL 5.14 and Apache virtual hosting all of these gives you a different result:

$CGI->virtual_host() returns DNS name ex. www.my.address.com
$ENV{'SERVER_NAME'} returns "localhost"
$ENV{'HTTP_HOST'} returns "localhost:8001"
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The actual values of course depends on you environment setting.

--
tune

JK_Bean, just a heads up...you should be using $ENV{'HTTP_HOST'}, i.e. %Env should be %ENV.

yes, you are right. that was a typo. my code does in fact use $ENV, all caps.