OK... let me get out my Acme® brand flashlight here. When I run a script that basically just dumps all the elements of the %ENV hash on my server here is a sanitized version of what I get back: 

DOCUMENT_ROOT     /path/to/doc/root/www.mydomain.com
GATEWAY_INTERFACE     CGI/1.1
HTTP_ACCEPT     text/xml,application/xml,application/xhtml+xml,text/ht
+ml;q=0.9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;
+q=0.2,*/*;q=0.1
HTTP_ACCEPT_CHARSET     ISO-8859-1,utf-8;q=0.7,*;q=0.7
HTTP_ACCEPT_ENCODING     gzip,deflate
HTTP_ACCEPT_LANGUAGE     en-us,en;q=0.5
HTTP_CONNECTION     keep-alive
HTTP_HOST     www.mydomain.com
HTTP_KEEP_ALIVE     300
HTTP_USER_AGENT     Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.2) 
+Gecko/20040301
PATH     /usr/local/bin:/usr/bin:/bin
QUERY_STRING     
REMOTE_ADDR     4.3.2.1
REMOTE_PORT     33161
REQUEST_METHOD     GET
REQUEST_URI     /cgi-bin/fooCheck.pl
SCRIPT_FILENAME     /usr/web/www.berghold.net/cgi-bin/fooCheck.pl
SCRIPT_NAME     /cgi-bin/fooCheck.pl
SERVER_ADDR     1.2.3.4
SERVER_ADMIN     webmaster@mydomain.com
SERVER_NAME     www.mydomain.com
SERVER_PORT     80
SERVER_PROTOCOL     HTTP/1.1
SERVER_SOFTWARE     Apache/1.3.29 (Unix) AuthMySQL/2.20 PHP/4.3.4 mod_
+perl/1.24 mod_ssl/2.8.16 OpenSSL/0.9.7c
UNIQUE_ID     QHMCUdiLkw8AAAVExU8

[download]

A quick glance reveals a value for REMOTE_ADDR which when I check the NAT'ed address for my client what I see there matches what I know my NAT'ed IP address to be.

AHA!

There-in lies one of the problems a coder has in trying to capture IP addresses of browsers. If the browser client is behind a NAT'ing firewall then all you are going to collect is the NAT address. Most network admins that do NAT use a single address for multiple desktop clients and individual IP addresses only for machines they want visible to the outside world. My home network is one of those.

If you are interested here is a subset of the code that generated that output: 

use CGI qw(:all);

print header,start_html;
env_test();
print end_html;

exit(0);
sub env_test {
  print h2('Base Account (shell) Environment');
  print table(
              map { Tr(td($_),td($ENV{$_})) } sort keys %ENV
             );
  print p(b('CGI Runs As:'),`id`);
  print p(b('Current working directory is:'),`pwd`);
  print p("I was invoked as: ",$0);
  if ($ENV{HOME}) {
    if (-d $ENV{HOME} . '/cgi-bin') {
      print p('Found the cgi-bin directory in ', $ENV{HOME} . "/cgi-bi
+n");
    } else {
      print p("I have no clue where the cgi-bin is physically");
    }
  } else {
    print p(b('OH DRAT!'),'The $HOME variable is not being set!');
  }
}

[download]

In reply to Re: Using CGI (Perl) and javascript at the same time by blue_cowdawg
in thread Using CGI (Perl) and javascript at the same time by krt6

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