I have a router with only 1 ethernet interface on a vps, on this router i have BGP routing in a /24 IPV4 and /29 IPV6 range. from there i use GRE and 6to4 tunnels to use the ip adresses on remote locations. I need a good firewall for the scenario where i want to close everything down, and then open up manually for some servers. i.ex. an Exchange server, Webserver, DNS servers, storage servers etc.
Anyone has a good firewall setup to share for this situation?