Allow SSH connections while using VPN
ip rule add from x.x.x.x table 128 ip route add table 128 to y.y.y.y/y dev ethX ip route add table 128 default via z.z.z.z
Where x.x.x.x is your public IP, y.y.y.y/y should be the subnet of your public IP address, ethX should be your public Ethernet interface, and z.z.z.z should be the default gateway.
Block and IP Address
iptables -A INPUT -s 18.104.22.168 -j DROP