Error when initialize rosdep

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I'm using Raspberry Pi 3 (Raspbian Jessie PIXEL). I'm trying to install ROS based on this tutorial: http://wiki.ros.org/ROSberryPi/Instal... .

The error I got is:

sudo rosdep init
ERROR: cannot download default sources list from: https://raw.github.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list
Website may be down.

I read a solution on this link http://answers.ros.org/question/54150/rosdep-initialization-error/, but I don't know what is the proxy server and host of my Raspberry, and I don't know how to find it too? (I'm quite new to both Raspberry and Linux, but I need to install ROS for my project).

And when I browse the link on the error, the website cannot be opened and it says "Your connection is not private".

Can anyone explain a little bit detailed how to find proxy server and port, and what to do next to fix this problem?

Thank you.