Yes they are all email ports. Do you directly connect to the internet from your computer or via a Router/Modem ? If you connect via the router/modem you will need to check on there for any port restrictions.
not true. ports can also be opened in firewalls. because all you are doing on the router is opening ports on its hardware firewall.
if you are using a router you will need to type the IP of the router into a browser (usually either 192.168.0.1 or 192.168.1.1) and configure it from there.
if you are using windows firewall you can go control panel-> windows firewall -> exceptions -> add port and enter them in there.