iptables suck, ufw using

https://help.ubuntu.com/community/IptablesHowTo

sudo ufw status numbered

sudo ufw delete allow 80/tcp

https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-with-ufw-on-ubuntu-14-04

ufw allow from 192.168.1.106 proto tcp to any port 22

sudo ufw allow from your_other_server_ip/32 to any port 27017

sudo ufw status verbose

ufw allow 22/tcp

https://docs.mongodb.com/manual/tutorial/configure-linux-iptables-firewall/