*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p tcp -s 198.51.100.0/24 --dport 443 -m conntrack --ctstate NEW -j ACCEPT
COMMIT