Using proxy in non-browser applications

My college uses a proxy server to provide internet. I am able to access internet on the browser very well and apps like Skype are automatically connected when I login into my browser. But some apps show error in connecting. In Windows Store (of Windows10) I am able to open the store but while downloading it shows an error code of 0x800704CF.

Also I am not able to access the internet in the terminal of my virtual machine - Ubuntu 16.04.2 LTS (I am able to access it in its browser). I get following errors:

While trying

sudo apt-get update

I get the error

Err:1 http://us.archive.ubuntu.com/ubuntu xenial InRelease
Cannot initiate the connection to us.archive.ubuntu.com:80
(2001:67c:1562::19). - connect (101: Network is unreachable) [IP:
2001:67c:1562::19 80]

And while trying

python get-pip.py

(after downloading get-pip.py)(to install pip) I get the error:

 Retrying (Retry(total=4, connect=None, read=None, redirect=None))
after connection broken by
'NewConnectionErro ('<pip._vendor.requests.packages.urllib3.connection.VerifiedH
TTPS Connection object at 0x7f7451ef1f10>: Failed to establish a new
connection: [Errno 101] Network is unreachable',)': /simple/pip/

I have tried to apply the proxy settings on terminal (in Linux) as:

 export http_proxy={proxy IP they provided}

but it did not work.

For apt you have to provide Configuration

• proxy conf for apt

For pip you can use command line arguments pip install --proxy user:password@proxyserver:port <package>