On my Windows 7 PC, I installed VMware VM for Linux Mint 15. Windows PC is behind corporate firewall /proxy server. Now inside Linux I issued:

sudo apt-get install python-virtualenv

Then created ~/projects folder and python virtual environment:

mkdir projects
cd projects
virtualenv venv

Then activated my virtual env:

. venv/bin/activate

So far no problem. Then tried to install python libraries, for example markupsafe:

pip install markupsafe

It throws an error:

Cannot fetch index base URL https://pypi.python.org/simple/
Could not find any downloads that satisfy the requirement markupsafe
No distributions at all found for markupsafe
Storing complete log in /home/me/.pip/pip.log

Inside pip.log I found:

<urlopen error [Errno 104] Connection reset by peer>

Installing any other library throws similar error. What's wrong here?