I want to block access to port 6379 on my server, but I still want to connect to it internally. The redis-server application runs on that port and I want to connect to it only locally (127.0.0.1). How can I do this?
To do this, you need to make sure that your IPTables rules are configured properly. Ubuntu generally leaves their servers wide open by default, which is why I still don't recommend their use as servers unless you are quite well aware of how to do this properly already.
I imagine that your
It's empty and it's wide open. The Ubuntu IPTables HowTo will probably help quite a bit with this. (https://help.ubuntu.com/community/IptablesHowTo)
I recommend something like this, which allow SSH on any interface and tcp 6379 any interface but the one you don't want:
You would then save this file in /etc/iptables.rules.
Obviously, any other ports that you specifically want open should be added.
Note: I've added the specific 6379 lines for clarity. The bottom ACCEPT right before the COMMIT would actually allow this because all loopback connections must be allowed on a Linux system for proper operation.
You will also want to put the rules in your /etc/network/interfaces file as well, to ensure that they are added when the interface comes up and not later in the boot process. Adding something like this is recommended:
Edit: To load this configuration initially, you need to run the iptables-restore command referenced above:
Well, I would suggest to use the "uncomplicated firewall" (ufw), which is also recommended by canonical. Reading and writing iptables is too complicated for just occasional port locking tasks.