If your port number is showing up as 
Download: Pat Benatar, Found: 40 Results, Updated: 27-Sep-2018. Pat Benatar Synchronistic Wanderings Box Set, 2 years, Music, 81, 1.53 GB, 1, 0.
RED in the Peers List or it says FIREWALLED under your username stats, then the tracker has determined that you are firewalled or NATed and cannot accept incoming connections. This means that other peers in the swarm will be unable to connect to you, only you to them. Even worse, if two peers are both in this state they will not be able to connect at all. This has obviously a detrimental effect on the overall speed.The first thing to do if this happens to you is to determine if you really are firewalled or if the tracker gave a false positive when it checked you out. So, head on over to CanYouSeeMe.Org and check to see if you really are firewalled. If it says you are not, but TTD is saying you are, try stopping your torrents, waiting a moment, and then starting them again. This will very often get rid of the FIREWALLED link under you name if you really aren't firewalled.
Pat Benatar Shadows Of The Night
If you really are firewalled, the way to solve the problem involves opening the ports used for incoming connections (the same range you defined in your client) on the firewall and/or configuring your NAT server to use a basic form of NAT for that range instead of NAPT (the actual process differs widely between different router models. Check your router documentation and/or support forum. You will also find lots of information on the subject at PortForward).
Pat Benatar Songs
These other links should also be helpful:
Why is Being Firewalled Bad? - I liked this explanation. It's simple and to the point.
Linksys Router Setup
CanYouSeeMe.org - Open Port Check Tool - verify that your port is open or closed (another site is NAT Check - check your port forwarding and bittorrent setup)
PortForward.com - Free help setting up your router or firewall
Port Forwarding for Windows XP
Tweaking your system to get the most out of BitTorrent - great read on how BitTorrent works and why you should forward your ports
Haley Giraldo
Just an added note about being firewalled: It is entirely possible to get high upload and download speeds if you are firewalled. Being firewalled simply means that you may not talk/connect to anyone else who is firewalled. So, if a lot of people on the torrent are not firewalled, then you can get great speeds. However, if most of the people on the torrent are firewalled, then your speeds are greatly limited to only being connected to those that are not firewalled (and, don't forget that all the other firewalled people may only connect to those that aren't firewalled so the non-firewalled people are forced to send out their data to a lot of people and thus can only upload at a small rate to any one person).