Hello Firas,

Thanks for your quick reply.

1. What do you mean by "Real"?

Even though its an private IP address, it uses DHCP for getting the IP address.( Its not static or aliased) I am able to access the Internet from the proxy machine.

2. By (Interface to the Internet), I suppose you mean that this private IP address will be NATed at another network device after the TPROXY. How about subnet 192.168.22.0/24? Is it NATed ? Why are you using two IP addresses on the TPROXY?

Yes, its NATed after TPROXY. 192.168.22.0/24 is not NATed.

I am using two IP addresses, because I want to create a local network behind 192.168.150.10 machine. I suppose, without two IP addresses I cannot create a subnet. Please correct me if I am wrong.

3.The TPROXY will spoof the IP addresses of clients on 192.168.22.0/24 subnet and I think (but I'm not sure) that TPROXY would send SYN-ACK to the original client, only after it receives SYN-ACK from the web server. Since this subnet is private, requests will not reach the web server unless you're doing NAT somewhere after the TPROXY. Please note that even if you're doing NAT, you must make sure that replies return back to the TPROXY rather than the original client.

Well, I checked with my setup. After the SYN packet from the client is received. The TPROXY machine never responds to the original client or even never tries to send the SYN packet to the web server.

Without using TPROXY, my setup with Iptables REDIRECT works fine.

4. I don't know about the internals of the TPROXY. Does it works with matching using IP address and port or with MAC address.

I could not get your question here!

What I meant here is, how does the TPROXY matches the packets. Since I am using the same MAC address for both the IP's. Will that be a problem?

Best Regards,

Yash