Generating SSH keys between git local and remote repository over proxy - linux

Question

I am using CentOS7.
I have tried to set connection between my local git repository and remote git repository on github.com. But my local repository is at work and it is behind the proxy.
I have found a lot of answers on stackoverflow about this problem. Maybe I am not so attentive and so on...but I haven't resolved my problem yet.
My steps were:
Creation of repository at github.com
Generating SSH keys using this tutorial https://help.github.com/articles/generating-ssh-keys/
But on "Step 5: Test the connection" in link-tutorial after using command ssh -T git#github.com
I was a little bit confused.
Connection did not work and I got this error:
ssh: Could not resolve hostname github.com: Name or service not known
Blockquote
At first I tried to set proxy in git config file:
git config --global http.proxy http://http://192.168.32.2:3128 But the result was the same I couldn't connect to my remote repository.
Next step was to set address of github.com in /etc/hosts as : 192.30.252.0 github.com
Address for github.com I took from here https://help.github.com/articles/what-ip-addresses-does-github-use-that-i-should-whitelist/.
After using command ssh -T git#github.com everything just hang up.
Despite the fact that connection through ssh did not work I tried to clone repository from my remote github account to my local account at work: git clone https://github.com/Nit84/hello-world.git. And everything copied as it should be and without any password.
At this point I just got stack. And I haven't the faintest idea what to do further.
Here is a list of my configurations using git config --list:
[root#localhost hello-world]# git config --list
user.name=Nit84
user.email=blob#gmail.com
core.editor=vim
http.proxy=http://192.168.32.2:3128
core.repositoryformatversion=0
core.filemode=true
core.bare=false
core.logallrefupdates=true
remote.origin.url=ssh://git#github.com/Nit84/hello-world.git
remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
branch.master.remote=origin
branch.master.merge=refs/heads/master
and here is the verbose mode of ssh -vT git#github.com:
[root#localhost hello-world]# ssh -vT github.com
OpenSSH_6.6.1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /root/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 56: Applying options for *
ssh: Could not resolve hostname github.com: Name or service not known
Is there any way to resolve my problem with connection between git local and remote repository using ssh-keys over proxy? Simply saying I want my command ssh -T git#github.com works as it is described in genereting ssh keys