What port does ethernet internet sharing use?

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mbezzombezzo
Posted:
in Genius Bar edited January 2014
Hi,

I just got cable internet today (YES!) and it's all wireless, which is wonderful. I do, however want to share internet through ethernet to my G4 tower. I am recieving net access wirelessly through my PB, and am then turning internet sharing on. It works great. Nice and easy to set up and everything, but as soon as I fire up OS X's firewall, internet stops working on the G4. How can I check to see what port is being used so I can open it? I'm not sure how to do something like that.



Thanks,

Matt

Comments

  • Reply 1 of 7
    gargoylegargoyle Posts: 660member
    Errrm, still saving to replace my pc with a nice shiney mac, but will try to answer this as best I can using general networking ideas that might help you solve your problem.



    1.) by the sounds of it, you PB is using NAT (network address translation) for its ics. This system does not use any specific port. Instead when a packet comes from your Tower, the PB translates its source address and sends the packet to the internet "on behalf of" the Tower. When the reply comes back the PB does the reverse.



    This works for any network request, be it http (port 80) ftp (port 21) or telnet (port 23).



    If your firewall has the option you might be able to "explicitly trust" your Tower for inet access.



    2.) The other, less common, way for ics to work is that your PB might be running "proxy" software. For this to work the clients (your tower) have to be setup to request all info from a single port on the PB, normally port 8080.



    Hope this helps... sorry that I cannot yet be osX specific.
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  • Reply 2 of 7
    defiantdefiant Posts: 4,876member
    under the sys. preferences in OS X, there is also a 'firewall' tab ( in the 'Sharing' tab). you should be able to activate the right port there.
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  • Reply 3 of 7
    mbezzombezzo Posts: 77member
    Thanks guys,

    Defiant - that's exactly the problem though, I don't know what port to open. The OS X Firewall doesn't mention anything about internet sharing.



    I'm surprised it doesn't automatically open the right port(s), all the other web services automatically adjust the firewall, like web sharing and file sharing... hmm
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  • Reply 4 of 7
    defiantdefiant Posts: 4,876member
    to clear things up:



    the internet comes through your powerbook wirelessly.

    how is the powermac connected to the internet? with an ethernet cable from the powerbook? or directly to the basestation?
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  • Reply 5 of 7
    paulpaul Posts: 5,278member
    PM to the pb...

    port 80 is http requests... i don't know any other common port, so ask around... the 2nd reply really gave some good info...



    hth
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  • Reply 6 of 7
    mbezzombezzo Posts: 77member
    Defiant-

    Yeah, internet is coming to my PB wirelessly, then I have an ethernet cable hooked up to my PowerMac from the PB.





    Paul-

    I'll try opening up port 80 and see what happens.

    The info is good, I agree, I just can't seem to make it apply to OS X's firewall.









    Thanks again
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  • Reply 7 of 7
    mbezzombezzo Posts: 77member
    Cool! Opening port 80 worked!



    Thanks!
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