24.02.2018 7:44 PM "Rafal K" <r99@wp.pl> napisał(a):

> ping 192.30.253.112
> PING 192.30.253.112 (192.30.253.112) 56(84) bytes of data.
> 64 bytes from 192.30.253.112: icmp_req=1 ttl=52 time=121 ms
> git clone git://github.com/lmsgit/lms.git lms
> Cloning into 'lms'...
> fatal: unable to connect to github.com:
> github.com[0: 192.30.253.112]: errno=Connection refused

git nie pracuje via icmp. 
raczej:
ssh -T git@github.com
telnet  192.30.253.112 22
ssh -T -p 443 git@ssh.github.com

spróbuj po prostu:
git clone https://github.com/lmsgit/lms.git lms

być moze http_proxy czy https_proxy trzeba ustawic abys mial na tym hoscie internet.