Disable incoming requests on Public IP

Hi guys,

Set up a droplet having the private networking option enabled. My aim is to:

1. Keep internet available on the droplet (so killing eth0 interface is not an option).
2. Block all incoming traffic from the internet.
3. Communicate with the droplet using the private IP (from another droplet).

I tried both these iptables (flipped order between two options), to absolutely no avail:

:INPUT ACCEPT [3:180]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [255:30170]
-A FORWARD -i eth0 -j DROP
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
COMMIT

and

:INPUT ACCEPT [3:180]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [255:30170]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -i eth0 -j DROP
COMMIT

Testing the changes this way: Go on another droplet, and ssh using both of these: ssh username@targetpublicip and ssh username@targetprivateip

In both cases, both keep working fine.

When I tried just this in the iptables: iptables -I INPUT -i eth0 -j DROP

I couldn’t SSH using the private IP either.

I’m using the ams2 datacentre for both droplets.

Thanks and regards