How to test cloud based https url connectivity from Linux server via proxy server

Posted on 2013-10-11
Medium Priority
Last Modified: 2013-12-12
Hi experts,

1. How to test cloud based https url connectivity from Linux server via proxy server (e.g https://xxxx.com./somecontext)
2. Unfortunately, I cannot install any utility on the Linux server (I do not have root access)
3. but I can copy any jar/files to test this connectivity.
3. Saw some link, testing using telnet but that’s not helping…getting invalid command. Think this command is not supported?

Thanks in advance
Question by:enthuguy
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LVL 13

Expert Comment

by:Daniel Helgenberger
ID: 39565265
can you please elaborate on what exactly you want to test? I figure, you are developing a Java application for a company witch will use this through its proxy?
Can you please clarify some points:
- The http(s) server is a public (cloud based) machine?
- Your linux server - is what exactly? Is it some server in your local network? Is it the only one witch needs access via proxy?
- The proxy server, is this a machine on your local network or something witch is in the http path in general?
- On which servers do you not have root rights but only FTP access (it seems)

General note: Access via proxy is something you cannot influence on your http server but this is the job of the proxy. HTTPS in general is not proxy'ed - do to the nature of the protocol. Bu this is highly subject to the person setting up a local proxy.
If my above assumption is true, it will do if you install the same proxy on your localhost; have it listen on loopback, and set your browser to use the loopback-proxy.

Author Comment

ID: 39567449
Hi helge, sorry for the lack of info.

- I have a endpoint (https url) given by a cloud vendor. We use this URL to import data onto the cloud app. This cloud app as two interfaces,
        1,  java based utility to import data. we had downloaded this java app on my linux server (jump box) and by using this java app we send data/xml to cloud app.
        2, Webservice interface, which other applications uses to send real time data.

I use java based util (option 1). Which was working fine few days before

- Linux server is kind of a jump box in our local network. Where it uses/invokes downloaded java to import data into cloud based https endpoint. This linux server makes call via proxy to cloud app (outside world).

- Proxy server is another machine in our local network...I believe.

- On the Linux (jump box), I do not have root access. But I can upload jar/util to help my issue.

- As I mentioned above, there is another linux server (middleware) which uses same proxy server to make webservice call to the same cloud app (not using java utility that I use). This works fine without any issues.

1. Linux Server/Jump box > Java util > same proxy server > same cloud app. Failing with not reachable. Once again, this was working fine few days before. It just stopped working now.

2. Linux Server/middleware > webserivce call > same proxy server > same cloud app. Works fine.

3. From cloud app admin web interface, I can see middleware calls coming thru, but not the jumpbox/java util call from audit log.

I was assuming something has changed in the proxy server settings (whitelisting jumpbox) and also thinking there could be some way to test connectivity test.

Assuming, we have a method to test, if I test from jumpbox it should fail. If I test from middleware server, it should pass

Thanks again
LVL 13

Accepted Solution

Daniel Helgenberger earned 1500 total points
ID: 39567731
Thanks for the info.
To test the proxy, the tool of choice would be curl. I hope you have ssh shell access to the linux jumpserver?

If you have some kind of ssh access use curl, I posted the full output so you can compare it. Should be the same for you:
$ curl http://www.google.com/index.html
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.de/?gws_rd=cr&amp;ei=8_FYUpDnB6OC4gT7wIC4Bw">here</A>.
$ curl https://www.google.com
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<H1>302 Moved</H1>
The document has moved
<A HREF="https://www.google.de/?gws_rd=cr&amp;ei=rPlYUvmYD4ek4AT1nYG4Dw">here</A>.

Open in new window

which will show you the index.html of google via HTTP and HTTPs. Please also curl something from your actual cloud service there.

If you have not this output, you are not permitted on the proxy or there is any other network related problem:
$ echo $http_proxy

Open in new window

may show you your proxy. If you have any output, unset it and try again:
$ http_proxy=
$ curl http://www.google.com/index.html

Open in new window

But most commonly you will have a transparent proxy; so you will need to test it in other ways.
Do you know what the java app does exactly? Maybe just plain GET/POST/PUTs? All of these requests can be done with curl as well.

If you do not have ssh access:
You can try this java script:
I am no java developer, but it seems to do the job. Anyway you can write some java script making http/s requests to well known sites like google.com.

If anything fails, you can still use the telnet method. But you need to know the actual proxy server on the network for this since you need to telnet to the proxy.

Author Comment

ID: 39568099
Hi helge, thx for the suggestions. Will try that monday.

What is the telnet way? could you help on that pls? how to test it with sample commands?

Thanks again
LVL 13

Assisted Solution

by:Daniel Helgenberger
Daniel Helgenberger earned 1500 total points
ID: 39568133
Basically you are doing the stuff a server would do manually. This involves 'telneting' into a remote machine and executing commands. Since the service you are calling cannot tell the difference between you and for instance a web browser, you can find out whatever this service is working or not.

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