detecting protocal and redirecting to https

If you use

if($_SERVER["SERVER_PORT"] != "443")

you always must have your https webs under 443 tcp port and this is not always true. Sometimes, tcp ports like 8443 are used to https.

You can use $_SERVER["SERVER_PROTOCOL"] and search inside for http or https

According to the Standards:

'HTTPS'
Set to a non-empty value if the script was queried through the HTTPS protocol.
Note: Note that when using ISAPI with IIS, the value will be off if the request was not made through the HTTPS protocol.

'REMOTE_PORT'
The port being used on the user's machine to communicate with the web server.

So,If you are using IIS then the above (fist) one is ok.other wise the value will be empty.
In case of PORT, if you use default port to install SSL Certificate,the above code(second) is good,other wise you have to know the port on which your site is working.

So,Which should you use,it tatally depends on you.Both of it will work in the same context.

This is my teaching example of how to get HTTPS only.  HTH, ~Ray

<?php // RAY_https_only.php
error_reporting(E_ALL);


// DEMONSTRATE HOW TO RESTRICT A SCRIPT SO THAT IT ONLY RUNS BEHIND HTTPS


// IF NOT HTTPS
if (empty($_SERVER["HTTPS"]))
{
    // CONSTRUCT THE HTTPS URL WE WANT, PRESERVING GET VARS
    $my_uri
    = 'https://'
    . $_SERVER["HTTP_HOST"]
    . $_SERVER["REQUEST_URI"]
    ;

    // BAIL OUT WITH 301 AND LOCATION
    header("HTTP/1.1 301 Moved Permanently");
    header("Location: $my_uri");
    exit;
}

// ELSE WE ARE ALREADY IN HTTPS - START SESSION FOR HTTPS ONLY IN ALL SUBDIRECTORIES AND ALL SUBDOMAINS
$x = explode('.', strtolower($_SERVER["HTTP_HOST"]));
$y = count($x);
if ($y == 1) // MAYBE 'localhost'?
{
    $cookie_domain = $x[0];
}
else // SOMETHING LIKE 'www2.atf70.whitehouse.gov'?
{
    // USE THE LAST TWO POSITIONS TO MAKE THE HOST DOMAIN
    $cookie_domain = '.' . $x[$y-2] . '.' . $x[$y-1];
}

$sess_name = session_name();
if (session_start())
{
    // MAN PAGE: http://us2.php.net/manual/en/function.setcookie.php
    setcookie($sess_name, session_id(), NULL, '/', $cookie_domain, TRUE, TRUE);
}

Select allOpen in new window

Notice that Ray's solution won't work in IIS, which is the case in question ...
YES, in IIS, this:

$_SERVER['HTTPS']=='off'

...will return TRUE if the request was not for https.

NO, you must not rely on the port number.
This is a matter of efficacy, not efficiency, as both things you are trying to compare are exactly the same from an efficiency (memory, processing) point of view.
It's a matter of efficacy, because one method (port number) will fail more often than the other.

From the question, I did not get that this was IIS (and I would never use IIS anyway), but if it is a question for IIS, maybe someone can take my code which works correctly on *nix systems and show the Asker how it can be done in IIS.  @prowebinteractiveinc: You might save yourself some time if you run this script (shown here in its entirety) on both HTTP and HTTPS platforms and compare the output carefully.  The parts you want to see are likely to be near the bottom of the output.

<?php phpinfo();

Select allOpen in new window

Best to all, over-and-out, ~Ray