I'm at a public library (france). I have a http library login to access that wifi.

I just want to download some SFML zip to make some app, but many things are blocked, mainly https. I can't even access my gmail account. Must be for some security reason, they might like to be able to log everything. Seems all proxies are also blocked.

One person once told me that https might not work, or that sometimes Mac can have problems connecting. For example when I type enter into the Chrome omnibox, it seems to always get an error because it defaults to https. I only can access google with firefox on http://

I don't want to hide that fact I'm doing that, I just want some way of getting that file, I won't just go back to home and then come back here, even if that takes 20min to download it.

I don't want to create a linux proxy etc, I just want to know why macs are having connectivity problems.

  • even reddit fails to login – jokoon Feb 7 '13 at 11:42
  • I think this question as currently worded is far too localized for this site (it only applies to one library in France). Could you rewrite the question, perhaps emphasizing no "what is wrong here", but "What techniques would help me to isolate the problem?" – Mark C. Wallace Feb 7 '13 at 14:55

It could be a proxy issue. Modern operating systems and/or browsers try to automatically obtain a Proxy Auto-Config file which is a piece of Javascript which tells which proxy to use for each target URL. Possibly, the PAC file exists and does something which confuses your Mac.

Open a Terminal and, in it, try this:

telnet www.google.com 443

If it fails to connect, then the port is blocked. If connection succeeds, close it, then try this:

openssl s_client -connect www.google.com:443

If that command makes the SSL/TLS handshake successfully, then this means that HTTPS works, and you have a proxy issue. If it fails (but the telnet succeeds), then this means that the library network plays funky games with the SSL filtering.

If HTTPS works for Windows systems, you could run a Windows system in a virtual machine and browse/download from that system... because the VM has low-level access to the network interface and will be immune to whatever MacOS X thinks about proxies.

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    DNS may be blocked (or redirect to an information page) in such a restrictive setup as well (in fact, the admin may just not route anything add all, and thereby require a proxy for any traffic to/from the Internet). To check whether it's just DNS blockage, you may also want to try telnet 443. – phihag Feb 7 '13 at 12:09

You can tunnel many VPN implementations through HTTP. For example, obfsproxy allows this for Tor.

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  • link doesn't even work, even in plain http. – jokoon Feb 7 '13 at 11:59
  • Sorry, for security reasons, you must download that software beforehand from a secure connection. Note that this site is for security questions. If you just want to download something once, ask on superuser. The easiest way to accomplish that is probably to ask someone to mirror the files you want for you on an unencrypted HTTP server, but that's not secure in any way, especially if you're downloading software. – phihag Feb 7 '13 at 12:04

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