sudo apt-get install corkscrew on the client machine.
You need to figure out the proxy address if your corporate environment is dumb enough to use a non-transparent proxy, in my case it's 18.104.22.168.
grep "Port 443" /etc/ssh/sshd_config
Now with a
~/.ssh/config setup like so:
ProxyCommand /usr/bin/corkscrew 22.214.171.124 8080 %h %p host webc HostName webconverger.org Port 443
In my case I
ssh webc to freedom.