NixOS, hyprland, took me 3 days, enjoy
Situation: You play Tryhackme or HTB you can not do a reverse shell from outside to host through openvpn and you can not create a reverse shell from the machine -> host (nixos machine)
Why is this happen you may ask? Well NixOS have defined some firewall and they are not allowing all port, you need to modified this in:
networking.firewall.allowedTCPPorts = [];
or if you in a hurry and lazy change iptables rules. Here you can flush it all if you don't wanna think:
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo systemctl reload firewall
Hope this help someone, cheers