allow incoming ssh only and outgoing http(s).

iptables-save.txt

*nat
:PREROUTING ACCEPT [3468:453807]
:INPUT ACCEPT [7:412]
:OUTPUT ACCEPT [872:59514]
:POSTROUTING ACCEPT [872:59514]
:DOCKER - [0:0]
COMMIT
*filter
:INPUT DROP [30:5670]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [15718:1541508]
:DOCKER - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -s 192.168.0.100/32 -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state ESTABLISHED -m tcp --sport 80 -j ACCEPT
-A INPUT -p tcp -m state --state ESTABLISHED -m tcp --sport 443 -j ACCEPT
-A INPUT -p tcp -m state --state ESTABLISHED -m tcp --sport 53 -j ACCEPT
-A INPUT -p udp -m state --state ESTABLISHED -m udp --sport 53 -j ACCEPT
COMMIT