[feature-request] Network: Promiscuous mode for NAT

[Technologov]

Hi,

I have 2 VMs with SSH servers on my host. I use user-space NAT. Host has IP: 192.168.4.82

I would like to be able to make a NAT route from a different host IP, like 192.168.4.201 and x.x.4.202 for those 2 VMs. I would be nice if VirtualBox NAT router could enter into "promiscuous mode" and allow the host listening on custom addresses (similar to what WinPCAP/libpcap and Wireshark do).

Today I have to use non-standard ports for this. Like:

VM1:

Rule 1 | TCP | [blank host IP] | host port = 1001 | [blank guest IP] | Guest Port = 22

VM2:

Rule 1 | TCP | [blank host IP] | host port = 1002 | [blank guest IP] | Guest Port = 22

I would like to achieve this:

VM1:

Rule 1 | TCP | 192.168.4.201 | host port = 22 | [blank guest IP] | Guest Port = 22

VM2:

Rule 1 | TCP | 192.168.4.202 | host port = 22 | [blank guest IP] | Guest Port = 22

-Alexey Eromenko "Technologov", 6.July.2014

[Technologov]

Explanation:

Okay, the problem it solves, is it allows setting two-default-gateways, not normally possible under the TCP/IP model, but possible via VBox/NAT method. It solves some of the complex topology issues and corner cases with GNS3.

It allows PC1 and PC2 on my topology to have default gateway set into my private WAN simulator, but also be controlled from the Internet via VBox NAT.

-Alexey "Technologov"

[Technologov]

Screenshot: VBox-NAT solves two-default-gateways problem of TCP/IP.

[Valery Ushakov]

I'm not sure I understand what you are trying to achieve. So far it sounds like bridged networking. NAT itself doesn't route anything on the "real" side of things, it uses host's IP stack. ("NAT" is a misnomer in the first place, since it's not really a NAT in the conventional sense, it's more like a transparent automagic socks proxy).