Why is iptables not closing a port?

Question

linux

Good day. I try to close the iptables port from outside, but the rule does not work.

I have a service on port 81, in docker. I want the port to be closed through the external interface (except for one IP), I will go through Localhost

What I do - I
allow access to the port from my IP
iptables -A INPUT -s 188.242.111.111 -p tcp --dport 81 -j ACCEPT I

prohibit access to this port to external interface
iptables -A INPUT -i enp2s0 -p tcp --dport 81 -j DROP

output iptables -L -n -v

Answer 1

Docker has its own tables, and you edit the main ones. See real life withiptables-save

Answer 2

So just don't expose the service port to the outside in your docker-compose file:

ports:
    - "81"

Services will be able to communicate with each other, but this service will not be available from the outside.
And to do something there yourself, use docker exec

Answer 3

If so?

iptables -t nat -A PREROUTING -s 188.242.111.111 -p tcp --dport 81 -j ACCEPT
iptables -t nat -A PREROUTING -i enp2s0 -p tcp --dport 81 -j DROP

iptables -nvL -t nat

Answer 4

Little information, do you have internet on enp2s0 or some pppoe, tun?
look at iptables-save and ip add.
On counters 0 and on ACCEPT and on DROP

Answer 5

in order to work with containers, there is a DOCKER-USER table, add rules to it.
https://docs.docker.com/network/iptables/