I'm running VirtualBox 4.2.4 on a Windows 7 x64 host. I installed a Xubuntu guest system. The VM has network access through NAT. VirtualBox is configured to act as DHCP server (setup by default) and listens on 192.168.56.100. The IP address of the host on the LAN is 192.168.1.20, the router is 192.168.1.1.
So, after I installed Xubuntu, everything just worked, no problem connecting to the internet. I didn't configure anything.
However, I now want to share a folder in the Xubuntu guest and access it from the windows host. But when I look up the IP address of the guest it is 10.0.2.15. I don't understand where this comes from, I have no network with that address block.
I installed dhcpdump to have a closer look and sure enough, the DHCP request is answered by 10.0.2.2. I have no idea where that comes from.
I tried to traceroute this mysterious IP but that doesn't seem to work, just prints asterisks (but it seems that's another problem, it doesn't work with e.g. google.com as well).
I also tried to scan it using nmap but I'm not sure what to make of the result:
PORT STATE SERVICE VERSION 135/tcp open msrpc Microsoft Windows RPC 445/tcp open netbios-ssn 554/tcp open rtsp? 2869/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP) 5357/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP) 9000/tcp open cslistener? 10000/tcp open snet-sensor-mgmt? 10243/tcp open http Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP) 49152/tcp open msrpc Microsoft Windows RPC 49153/tcp open msrpc Microsoft Windows RPC 49154/tcp open msrpc Microsoft Windows RPC 49155/tcp open msrpc Microsoft Windows RPC Device type: printer|switch|remote management Running (JUST GUESSING) : Samsung embedded (87%), 3Com embedded (85%), Dell embedded (85%), Xerox embedded (85%) Aggressive OS guesses: Samsung CLX-3160FN printer (87%), 3Com SuperStack 3 Switch 4300, Dell PowerEdge 2650 remote access controller, Samsung ML-2571N or 6555N printer, or Xerox Phaser 3125N printer (85%) No exact OS matches for host (test conditions non-ideal). Network Distance: 1 hop TCP Sequence Prediction: Difficulty=17 (Good luck!) IP ID Sequence Generation: Incremental Service Info: OS: Windows
I don't get it. What's behind this IP address? How is it possible that it answers DHCP request in the VM guest?
I assume everything will work fine when I manually configure the correct DHCP server address but I'd really like to understand what is going wrong here and where this mysterious IP comes from.