Firewall problems reinstalling El Capitan (Education Customer)

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talksrm Author

Level 1

20 points

Firewall problems reinstalling El Capitan (Education Customer)

I am encountering a firewall related issue when setting up a fresh OSX install on a mac computer.

When following the points on this Apple KB article: https://support.apple.com/kb/ph21973?locale=en_GB&viewlocale=en_US

Everything works well until I get to the following part:

"6.Select Reinstall OS X, click Continue, then follow the on-screen instructions."

Once I select reinstall OSX, you must accept the licence conditions. After this step, I am asked to authenticate with my Apple ID.

It is at this point, that I encounter a problem.

I log in with my correct credentials, but they fail to work and and error is shown explaining that OSX is unable to verify my logon details. - Almost as though I am not licenced for El Capitan.

I have taken said mac home and repeated the same steps and it worked fine with my home broadband connection so I know this is isolated to my work connection. This is not the first time this mac has happened on, and again, as soon as I take the system home, it works fine.

My ISP is happy to resolve the issue, but they need me to tell them what needs opening up on our firewall.

Can anyone help me?

Mac mini, Mac OS X (10.7.3), null

Posted on Nov 30, 2015 3:42 AM

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Answer 1

lllaass

Level 10

210,417 points

Nov 30, 2015 5:53 AM in response to talksrm

Have you talked to your company's IT staff? It appears that your company's network is blocking the ports used.

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Answer 2

Nov 30, 2015 8:55 AM in response to talksrm

I have seen something similar happen when the network in question has a proxy server on it. User processes like the App Store, iTunes, Safari etc. can if needed display a dialog and ask for authentication details to access the proxy server. If however you booted in the special Internet Recovery mode, then it may not have this ability.

If this is the case then the following are possible solutions.

Get IT to find the address involved and define a bypass rule in their proxy server settings
Connect the Mac in question to a network connection that does not go via the proxy server if one is available at work, or do it at home, or take it to an Apple Store
If this is a work/education Mac that they are supposed to be supporting, they should be if needed re-installing your Mac for you, I for example support our company Macs and I have a DeployStudio system for reinstalling Macs
Download the OS X installer from the App Store, if you have previously purchased it then you are still allowed to re-download previous versions e.g. Mavericks, but anyone can get El Capitan free from the App Store, then you can use DiskMakerX to make a bootable USB stick which can re-install OS X for you

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