Hi @hellohello589,

You can whitelist IP addresses on your Droplet using IPTABLES. Good thing is DigitalOcean have a pretty good tutorial on how to work with IPTABLES. Here is the article:

https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands

For instance, if you wish to allow an IP address to your firewall you can se use the following commands

iptables -I INPUT -p tcp -s XXX.XXX.XXX.XXX -j ACCEPT
iptables -I OUTPUT -p tcp -d  XXX.XXX.XXX.XXX -j ACCEPT`

Please note you need to change XXX.XXX.XXX.XXX with the actual IP addresss. Additionally, the above commands will allow access to every port for the given IP Address.

If you want to give access only to IP only on a specific port, you can use

iptables -I INPUT -p tcp -s XXX.XXX.XXX.XXX tcp --dport 80 -j ACCEPT

Regards,
KFSys