My company use Microsoft ISA Proxy to block all type of connections, except HTTP & HTTPS (as far as I know). Even the ICMP packet is blocked (except sending ICMP to gateway).
Some domains are also blocked, youtube is one of them. But if I use proxifier, I could browse youtube smoothly.
I know how proxifier works, it redirect applications to operate through a SOCKS or HTTPS proxy and chains. In my case, I do not use external proxy at all. I only use my company proxy to browse the web. So, I could just set firefox to use my company proxy to browse the web or I could just set firefox not to use any proxy and set the proxy via proxifier. It logically the same things (right?), but the resulted actions are different.
Then how does proxifier really work?