How do I see what OUTBOUND ports are blocked?
Question by Matt M: How do I see what OUTBOUND ports are blocked?
I'm trying to plan for getting a SlingBox but where I go to college they restrict the ports to stop file-sharing and spammers (it's a public/open network). I want to be able to watch TV between classes (say while I eat lunch) but I don't want to waste money on a slingbox if it won't work.
Is there any way I can check what outbound ports are open? I know 80, 110, and 443 are allowed and most others are blocked...but not exactley what's what.
My home ISP blocks ports 80, 25, and 110 to stop home-servers from working. I'm already using port 443 for remote TCP/IP printing, so I'd rather not give that up...I haven't had time to try many others because it involves changing my home network, then checking when I get to class, and the next day repeating the process - so I can check one port a day...not very practical.
Is there some program that will scan all the ports (or a lot of them) and tell me what OUTBOUND ports work so I can narrow my search for a port allowed both out of my college and into my home?
I can't afford to get cellular/satellite internet for my laptop...
I understand at home it's inbound ports.
At college, it's outbound they restrict...I can't even send/recieve mail (ports 587/995). FTP, SSH, Telnet ports are all blocked at the college too...outbound - I can't access any server via those services.
Basically the only thing they intentionally left open is to browse the web.
Best answer:
Answer by Colanth
It's inbound ports that are - effectively - blocked. (They're not actually blocked, they're not available unless they're forwarded, and the school doesn't forward any ports to you.) Outbound ports, since they don't have to be forwarded, aren't "blocked".
"My home ISP blocks ports 80, 25, and 110 to stop home-servers from working."
That's inbound, not outbound. If they were blocked outbound you couldn't browse the web or receive or send email.
Give your answer to this question below!
January 9th, 2012 - 11:55
Nmap (“Network Mapper”) is a free and open source (license) utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and both console and graphical versions are available.
By scanning a public computer on the internet, you can learn what ports are blocked on your network. Read the documentation further for more information.
Keep in mind that use of this tool may be against the network policies of your school and could possibly get you expelled off the network, so use wisely.
If your looking for an outbound looking in scanner, try the following below:
http://www.hackerwatch.org/probe/