I'm running Centos 7 in a VM (I don't believe this should matter, but for context...)
Inside the VM, I'm running software to establish a tunnel. I can already accept connections from the host okay, but I want to force all outbound traffic over the tunnel.
How can I allow return packets for existing connections, while also ensuring no new connections are established from the box unless over tun0?
I've looked at this question iptables blocking all outbound connections but it appears a bit brute-force... I've been using firewall-cmd
and the output for iptables -L -n -v
is verbose.
Conversely, with Use specific interface for outbound connections (Ubuntu 9.04), I can't see how to apply it to centos.
How can I reliably ensure that all outbound traffic is either established over tun0 or not at all?