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I'm not sure if this belongs here or to Server Fault... but gotta start somewhere...

I'm running a Win2008R2 server on VirtualBox. This server has an SNMP application. I'm trying to make this application manage physical devices which reside in a remote test lab, to which I connect through our office VPN. The setup is as follows:

+--------------------+
| Win7 PC            |
| +----------------+ |
| | VirtualBox     | |
| | Win2K8 R2      | |  +-----------------------+           
| | 172.16.0.2/24  | |  | DSL Router            |           
| | DGW 172.16.0.1 | |--| LAN IP 192.168.1.1/24 |
| +----------------+ |  | WAN IP 1.2.3.4/31     |           
| LAN IP             |  +-----------------------+           
| 192.168.1.10/24    |          |
| DGW 192.168.1.1    |      +-----------+
| VPN IP 10.10.10.10 |      | Unknown   |
+--------------------+      | VPN       |
                            +-----------+
                                |
                            +------------+
                            | Some       |
                            | routers in |
                            | 10.0.0.0/8 |
                            +------------+
                                |
+-----------------------+   +---------------+
| Switch 10.100.0.50/2  |   | Lab Router    |
|                       |---| 10.100.0.2/24 |
+-----------------------+   +---------------+

When I add the switch to the SNMP application, the application registers on the switch as a trap receiver with IP address 172.16.0.2. When I ping the switch from the W2K8, the source address is the VPN IP of my PC, 10.10.10.10.

I can ping the VPN IP of my PC from the switch. However I can't ping the IP of the W2K8. The obvious reason is that there's no route to 172.16.0.0/24. And when I check the switch status regarding the SNMP application, I only see "Connecting". I've tried to configure the switch for mgmt. app IP 172.16.0.2 as well as the VPN IP 10.10.10.10 with no luck.

Configuring the Virtual Server IP to different modes produces these ping results:

Ping from the switch to my PC VPN IP is always successful. I can never ping the W2K8 from host OS - ipconfig doesn't show IP 172.16.0.1. The DSL Router WAN port won't respond to ping from the Internet side.

NAT or NAT Network:

  • With no proxy configured W2K8 has full Internet access, whatismyip.com shows the WAN IP of the DSL router
  • With office proxy configured W2K8 has full Internet access, whatismyip.com shows the office proxy IP
  • W2K8 can ping its DGW
  • W2K8 can ping the physical IP of my PC
  • W2K8 can ping the VPN IP of my PC
  • W2K8 can ping the DSL Router LAN IP
  • W2K8 can ping the DSL Router WAN IP
  • W2K8 can ping the Lab Router
  • W2K8 can ping the switch
  • Switch can ping everything else but the W2K8 IP

Bridged Adapter:

  • W2K8 gets IP address on my own network with DSL router as DGW, and can ping it
  • W2K8 has full access to the Internet
  • W2K8 can't ping the physical IP of my PC
  • W2K8 can't ping the VPN IP of my PC
  • W2K8 can ping the DSL Router LAN IP
  • W2K8 can ping the DSL Router WAN IP
  • W2K8 can't ping the Lab Router
  • W2K8 can't ping the switch
  • Switch can ping everything else but the W2K8 IP

Internal network:

  • W2K8 has no IP address so no ping

Host only:

  • W2K8 has "Media disconnected"

Some additional info:

  • I have a Debian system in the 10.100.0.0, which has a perpetual SSH connection to a RasPi in my own 192.168.1.0
  • I have full control over everything in 10.100.0.0 except for router .0.2 so I can for example configure both Linux boxes to route traffic
  • I have full control over everything in 192.168.1.0
  • I have no control whatsoever over anything else in 10.0.0.0

So: is there any way to make the W2K8 reachable for devices in 10.100.0.0?

1 Answer 1

1

The problem is the switch doesn't know how to get to the 172.16.0.0 network. And since you don't have control over the intervening devices, you can't add routes. If you had control over the router you could do some sort of tunneling. Otherwise, there's not much you can do.

1
  • That's why I was wondering if I can route through the SSH tunnel :-) I could configure the Linux box in the test lab to act as router and route traffic towards the RasPi or my home DSL where I can do port forwarding... but the how-to goes wayyy beyond my ken... Sep 29, 2015 at 15:30

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