Probably easiest way is to follow this:
http://portforward.com/english/applications/port_forwarding/Final_Fantasy_XI_-_PC/default.htm
Locate your router make and model on the list and the ports to forward.
The primary ports to forward are UDP 50000-65535 as these are used by the actual World servers themselves. 50000-65535 imply a range of ports from UDP 50000 to UDP 65535.
Your college may block ports TCP 25, 80, 110, 443 as those are web and mail server port numbers.
UDP and TCP are, simply put, different kinds of communication protocols that allow two different networks communicate with each other.
The most important thing to remember is that port forwarding only works if your computer has a static IP address. In other words, an IP address that does not change.
To set a static IP address in Windows 7 or 8, go to Control Panel then Network and Sharing Center. Or, alternatively, right click the network icon in the system tray then click on Open Network and Sharing Center.
On the left-hand side, click on Change Adapter Settings.
Next, find your network card.
(Mine is Ethernet 3 - TEAM 0. Yours will be different.)
Right-click it then go to properties. Locate Internet Protocol Version 4 (TCP/IPv4) and double-click it or select it and click Properties.
You want to select
Use the following IP address:".
Under "IP address:", have the first three numbers match both the gateway and router IP address.
For example, if your router's address is 10.148.1.1 then your IP address should start out as 10.148.1.xxx.
No number is to exceed 255 and certain numbers are reserved by the network. Keep that in mind.
Subnet mask should match what your router or gateway has. For example, my subnet mask is 255.255.248.0. However, the router has its own unique subnet mask that connects it to my gateway: 255.255.255.0. If you are behind a router or gateway, make sure your subnet mask matches it.
Your "Default gateway" is almost always your router's IP address. For example, my router is at 192.168.2.1. Therefore, my default gateway is the same address.
You can leave the DNS server addresses blank. If you leave it blank, it will use whatever your router or gateway is using, which is usually your ISP's own DNS servers.
Recommended DNS servers you can use alternatively are the following:
OpenDNS: 208.67.222.222, 208.67.220.220
Google: 8.8.8.8, 8.8.4.4
About.com has a short list of them here:
http://pcsupport.about.com/od/tipstricks/a/free-public-dns-servers.htm
More can be found with Google.
After you're done, click OK. It is optional to select Validate settings upon exit. If Windows cannot validate the settings, it'll revert it back to Obtain an IP address automatically. You do not want that.
Whatever you choose as a static IP address is the IP address that you will have ports forwarded to your computer from your router.
Possibly simplest way to explain the terms above:
Let's say you live at 12456 Nemo Street, Port San d'Oria, San d'Oria.
IP address - Your home address like 12456 Nemo Street. 12456 is your IP address.
Subnet mask - Your neighborhood or city like Port San d'Oria. Subnet masks define "network neighborhoods" with the difference being that if you join one subnet mask, you cannot see anyone else in another.
Default gateway - Your street like Nemo Street. Gateways tell the network what route, or "street", to take to find your computer between it and the router or gateway.
DNS server - Very simply, the phonebook and local directory. This translates the hard numbers of an IP address and resolves them to names and other information to make it easier to find a computer or server on the network.