Screen sharing behind a firewall-- What ports?

Question

Screen sharing behind a firewall-- What ports?

Hello.

I am trying to use Ichat screen sharing through a firewall. Anybody knows what ports should be opened? Definitely I can share screens with computers within the same domain, and I cannot as soon as I go outside, so it must be a problem of ports being blocked. I found no information in Apple's documentation about specific ports for screen sharing via Ichat.

Thanks for any info.

l.

Mac OS X (10.5)

Posted on Nov 14, 2007 11:50 AM

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Answer 1

RoryMac

Level 3

814 points

Nov 14, 2007 12:26 PM in response to Merged Content 1

If it uses the same ports as Apple Remote Desktop (which it should...)
tcp 5900 & 5988
udp 5900 & 3283

and you would need whatever port iChat uses open also...

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Answer 2

Nov 14, 2007 12:46 PM in response to RoryMac

Thank you RoryMac. I will try and post a follow-up.

best,

l.

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Answer 3

Nov 21, 2007 12:16 PM in response to Merged Content 1

Hey Lucabo,

Did you have any success? I have been having the same problem you described.

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Answer 4

Nov 22, 2007 8:55 AM in response to Wildatheart

Yes, for the moment only bad news.

With our engineer, we checked screen sharing from inside the firewall and from outside. It looks like when you do screen sharing, a random port is selected for communication -- not the tcp and udp ports used by Apple Remote Desktop. In our tests, they were ports on the order of 50 or 60 thousand something, varying each connection.

THis means that you can't just open 2-3 dedicated ports, that is of no use (at least, we didn't find how to do it). This in turn means that very few institutions will accept to let you use screen sharing, because they should open big ranges of ports.

If anybody else has some suggested solution, we can try it out.

Best,

l.

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Answer 5

Nov 22, 2007 3:42 PM in response to Merged Content 1

Many thanks for the heads up.

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