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I'm behind a corporate network with an HTTP proxy. I also have an SSH server to reach on port 22. I don't have any kind of control over that server: I'm not root and even if I were I'm not allowed to install software or change configuration. The server listens on port 22, must be reached there and this cannot be changed ever.
If I configure XShell
(but the same should apply to any other client) to use the corporate proxy I can't connect. Wiresharking it shows that CONNECT
method gets refused by proxy because "that's not an SSL standard port".
I believe that the proxy blocks traffic to ports other than 80 and 443. Without doing deep packet inspection or other esotheric tricks.
I have been linked an article about configuring HTTP proxy for SSH "when the proxy filters SSH protocol" but the problem is that it works for Linux and I have another problem with it (it doesn't detect network card, already asked here...).
The question is: how to bypass the proxy without installing software or changing configuration on the target machine?
I would also like to understand
- Since the proxy blocks port 22 instead of SSH protocol by deep packet inspection, does the linked guide work when the server listens on port 22 and cannot be changed any way ever?
- Is there a way to make it work on Windows?
At the "further docs are found here" link, corkscrew is not mentioned. I know this is a few years later, but - can you elaborate on how corkscrew "comes into the mix"? – einpoklum – 2019-11-03T23:46:36.147
Sorry. I said that the proxy blocks port 22 on the CONNECT invocation, it doesn't give the client the time to initiate SSH handshake. So no DPI, just port filtering and absolutely no way to change the machine's listening port – usr-local-ΕΨΗΕΛΩΝ – 2013-01-17T08:35:43.393
Question needs clarification. I can't install software on the target machine. I'm not root there – usr-local-ΕΨΗΕΛΩΝ – 2013-01-17T08:41:26.597
OK +1 because if I find another server where I can install software I can use it as HTTPS->SSH proxy to the target server. I might accept the answer, many thanks :) – usr-local-ΕΨΗΕΛΩΝ – 2013-01-17T08:47:07.927
The second link is particularly well made and detailed. I'm eager to test it! – user39559 – 2013-06-28T13:16:40.803