We have a distributed application composed of several different components. For example, we have Python app servers, PostgreSQL DB servers, Redis servers, Memcached, etc. Some of these services are in different servers. All of these servers are running CentOS Linux, and we are currently enabling access between servers only on a need-to-connect basis (i.e. instead of opening up port 6379 to all hosts in every Redis destination host, we open it per-host).
My question is: What is a good practice for managing iptables environments where multiple servers are concerned? Is there some other tool that I should be using, or is there a better management scheme for security between several servers? If there is something better than plain firewalls, let me know.
Any suggestions will be appreciated. Thanks very much for your time!