$_Server['Remote_Port'] Not Giving Value

php SERVER['REMOTE_PORT'] correctness

$_SERVER['REMOTE_PORT'] is the port making the request on the user's machine. That will be used to route back the page request to their router. This may look like a random number, but it's a port generated by the user's router.

$_SERVER['SERVER_PORT'] is the port on your web-server that is receiving the request. This will be either 80 or 443 depending on if the user is using https or not.

Here is another posted question on Super User that explains this phenomenon of browsers requesting a webpage from a "random" port -> https://superuser.com/questions/1055281/do-web-browsers-use-different-outgoing-ports-for-different-tabs.

Also, router in between the client and web-server may change the port and then store the port-connections in the NAT (network address table) in order to route the response back to the browser. -> https://superuser.com/questions/105838/how-does-router-know-where-to-forward-packet

From: CompTIA Security+ Get Certified Get Ahead: SY0-501 Study Guide - 2017 by Darril Gibson

Client-side ports start at ports 49,152 and increment up to 65,535....
...When you use your web browser to request a page from a site, your
system will record an unused client port number such as 49,152 in an
internal table to handle the return traffic. When the web server
returns the web page, it includes the client port as a destination
port. When the client receives web page packets with a destination
port of 49,152, it sends these packets to the web browser application.
The browser processes the packets and displays the page.

Also, from the PHP manual: https://www.php.net/manual/en/reserved.variables.server.php

'SERVER_PORT'
The port on the server machine being used by the web server for communication. For default setups, this will be '80'; using SSL, for
instance, will change this to whatever your defined secure HTTP port
is.

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

Can't Curl to PHP Page with $_SERVER Variables

The first script you posted has several syntax errors. When you call it via curl, you are getting an HTTP 500 error because it is throwing exceptions.

A few errors of note from testing:

• You do not close your foreach loop with a curly brace.
• Your series of nested if statements are missing curly braces.
• The $_SERVER superglobal will not be populated with all values when run from command line (just an FYI from my testing -- not necessarily an issue) resulting in several undefined index errors.

Work on that script separate and once it runs correctly, then you can call it from another one.

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