在Linux主机上，FTP自身（来自PHP）是否会生成出站流量？

Question

If I place a PHP script on a host, and in that script FTP a file (local to the script) to a FTP account also ending on that same host, my expectation is that the connection and transfer should be nearly instant as (I hope) no outbound traffic would be generated. But I don't have a way to test this. Is this really the case?

Update

1. The FTP host is not localhost, or 127.0.0.1. Say we have a normal FTP account johndoe with a ******* password on thehost.com. On this same thehost.com we execute our out_of_jail.php script that will FTP /css/styles.css to thehost.com.
2. This is supposed to work on host environments where the admin does not have access to /etc/hosts to add thehost.com.
3. Let's define outbound traffic in the most restrictive way, by it, we mean traffic that goes out to the network card. So, if it goes out and returned as an inbound packet by some other device in the same network, it would still be considered as outbound traffic.

Answer 1

If you point your FTP script to localhost or 127.0.0.1 then there should be no outbound traffic.

If all you're trying to do is get a file from Point A to Point B on the same server via a PHP script, there are other ways to do that besides FTP as well. Of course I do not know all the specifics of your scope or needs, so maybe the FTP approach is right for you. But if you can't get it working, look in to some other options.