Here is the network topology that I have:
Private network 1 --> IPFire Firewall 1 <---> IPFire Firewall 2 <-- Private network 2
I can ping from private network 1 to private network 2, that is after creating an IPsec tunnel between the two IPFire devices.
What I want to do is to have a middle device between the two IPFire devices, the network topology is like this:
Private network 1 --> IPFire Firewall 1 <-- middle device --> IPFire Firewall 2 <-- Private network 2
I want to use this middle device as a packet sniffer for the packets flawing between IPFire 1 and 2. What I don't know is how transfer the connection from one interface of the middle device to the second, the IPsec tunnel uses private IPs, so I don't know who the middle device will affect the tunnel establishment.