How do you sniff out holes in firewalls?

Discussion in 'Mac Apps and Mac App Store' started by excalibur313, Sep 15, 2003.

  1. excalibur313 macrumors 6502a

    excalibur313

    Joined:
    Jun 7, 2003
    Location:
    Cambridge, MA
    #1
    I'm behind a firewall at my college and I was wondering if there was a program I could use to figure out which ports are open so that I can route programs through them.
    Thanks,
    Excalibur313
     
  2. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #2
    Re: How do you sniff out holes in firewalls?

    There are a few factors you have to look at. But the biggest is: Are you trying to run something the college computer policies forbid. And after that, the fact that you're probing the firewall to look for openings could get you in trouble with the college as well.

    After you deal with the college rules and regulations, how you would search for a hole in the firewall depends on what you're trying to run. Different applications have different requirements.
     
  3. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #3
    Note the above warnings. Doing what I am about to suggest can be viewed as an attempted attack on the network!

    Open up the Applications/Utilities folder. Start the NetworkUtility app (named this or somthing similar). Click the Port Scan tab. Select a sensible range of ports (say 0 to 10000). Run it against the ip address of the firewall.

    Only do this if you are very sure you want to. Any decent network admin will see this happening and rip you a new one.
     
  4. excalibur313 thread starter macrumors 6502a

    excalibur313

    Joined:
    Jun 7, 2003
    Location:
    Cambridge, MA
    #4
    Oh I see. I thought that the reason why networks blocked off all but a very few specified ports was to block attempts for outsiders to get in. I thought that if you wanted to run a program you simply just ran it through the clearly specified ports. I didn't realize that it could be viewed as an attack on the network.
    Thanks,
    Excalibur313
     
  5. Lanbrown macrumors 6502a

    Joined:
    Mar 20, 2003
    #5
    Attacks happen internally and externally. A firewall is used to prohibit certain functions. If you don't want people sending mail, you can block SMTP from everyone or just allow one, like the SMTP server.
     
  6. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #6
    If you are given a list of specific ports to use, or an application works, this is not considered an attack.

    Running a port scanner looking for open ports is an attack.
     
  7. Chealion macrumors regular

    Joined:
    Jun 17, 2003
    Location:
    Calgary, Alberta
    #7
    You always try the port scan from ShieldsUp at grc.com. It works.
     

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