git has a very simple solution to see all the commits in a graphical form. If you need to understand all the commits history all you need is
git graphviz|dot -Tpng -o /tmp/a.png
This will generate a file called /tmp/a.png which will diplay the complete commit history.
firewalld by default does not allow packets that are dropped. In some cases, you need to find out if some packet is being dropped or not. For doing so you may want to enable logging of dropped packets with the following command:
sudo firewall-cmd --set-log-denied=all
This will enable logging all the packets and help you figure out if firewalld is dropping the packet.