NAT，Debian，iptables

Question

I'm not sure how to phrase this exactly, which is why I'm posting a question because maybe that will help me to phrase the question properly, but basically I have a machine (machine c) visible to machine b through a private network. Machine c has no connection to any other network, but machine b does. Machine b has a connection to machine a and machine c. How would I go about exposing the connection from machine c to the outside world (machine a), if I only have access to machine b? Basically, I started at machine a, and I have full access to machine b, but my networking understanding is too amateur to figure out if I need iptables or something else to do what I'm looking for. Thanks!

Answer 1

A <==> B <==> C

With the vague information you provided, it seems like you would forward traffic via the interface which connects C to B and then to A. There are various tools you can use for this, iptables is certainly one and ip route is another which I've used for some quick tests. Here's a link about ip route that should give you enough examples to get your self into a better situation.

Another way would be to use a SSH tunnel from C to A if you're trying to connect to something specific. So you could do something like the following on C:

ssh -L localhost:9000:machineA:9000 user@machineB

Links

• Linux Set Up Routing with ip Command
• SSH Tunnel Example