I've set up a default vagrant setup, and I'd like to be able to find out what i can from the host about the guest.
For virtualbox setups, what happens is there are some pseudo interfaces that you can use to route and firewall the guest outgoing connections. But, when using vagrant, i noticed the availability of a private space eth0 which is NATted through the host interface. Searching using iproute2 and looking through the procfs does not show any interface at all.
A while back I found the vbox driver bypasses all the usual methods to inspect interfaces from the host machine. Is there a way to find out more about the interfaces on the guest from the host, and which chain should i target to firewall traffic from this?
Strangely just to answer: to find the existence of the ip address in procfs, you'll have to check the /proc/net/fib_trie. Unfortunately, anecdotally, this doesn't work on some procfs.