Port forwarding: Add suggestion checking the firewall

Apparently it helped someone in hosting, so may as well have it here as a last resort.

Also, rented Linux servers will probably want to read this anyway so they can open the connection on their firewall, since it's def going to be what is stopping them.

src/en/server-hosting/port-forwarding.md

@@ -114,7 +114,7 @@ If you don't know the login credentials, some things you may want to try:
 1. Checking the router unit to see if there's a sticker or something
 2. Checking any documentation from your ISP
 3. Trying your wifi password
-4. Asking your parents
+4. Asking your family
 5. Trying common combinations like "admin" "admin"
 
 ### Step 2: Port forward
@@ -133,6 +133,22 @@ When you do find it, you'll want to look for some form of "add" button to add an
 
 Save the settings or something.
 
+If this failed too, we have one last check.
+
+## Check your computers firewall
+If you are certain you did not mess up the above (or you are using your regular rented linux server), our last hope is to check for if your computer has it's own firewall active and blocking the connection.
+
+If you are on MacOS or Linux you will have to do your own research. Especially on linux as there are many firewall programs.
+
+I will cover Windows here
+
+1. Search for "Windows firewall" and open it
+2. At the top, click on "Action" --> "New rule"
+3. Change the option to "Port"
+3. Type "1212" as the port and make it a tcp rule (or whatever you set your port to if you changed it)
+4. Ensure "Allow the connection" is selected and that the rule applies everywhere (domain, private, public)
+5. Name it anything and do the steps again for udp instead.
+
 If you did this step correctly, then maybe it works! If it still doesn't work, uhhhh...
 
 ## ISP Fuckery