Setup a network between a virtual Debian and physical XP host

Question

I wanted to install a Debian server then work on it from my physical XP through PuTTY with a SSH session. It only worked once. Actually, it failed shortly after authentication request.

I use a Windows XP physical computer linked to internet with a modem-router, a Netgear. Three other computers are on the network: 2 XP Sweet and 1 Ubuntu.

I've installed a virtual machine I plan to use as server for my network, it's a text-only Debian5 virtualized with Vmware player 3.0.1 build-227600. Its virtual network connection is set as bridged. I also have a graphical Debian virtual machine I set for tests, virtual network connection bridged as well.

Every machine in the network, physical or virtual, have fixed IP. They all ping the other machines in any direction you want.

I tried SSH sessions from my test Debian and it worked flawlessly. People from outside the network could also when I opened a route for them. After installing OCS-NG server on the virtual machine (through SSH from the test Debian), I've deployed (manually) the agents on the machines in the network, their inventories all appeared, except for my XPs. Similarly, I can access the web interface of OCS-NG from any machine of the network except this one.

It seems that from my physical machine, only ICMP packets can reach the virtual machine.

I thought at first it was a firewall problem from my machine but I've opened the required ports on the firewall of XP. Also after a test, I could SSH to the server of a friend, without problem.

I'm running low on ideas as to why both machines won't communicate.

Answer 1

For setup similar to your environment, I always add two NICs to my virtual machines: a NAT (or bridged) one, and a host only network. The host only network allows all my VMs and the host machine to talk to each other on known addresses. I don't use DHCP for my host only network, which allows me to write scripts on my host machine (be it Putty sessions or Xming menu items) which don't break when I connect to a different network. Also the host only network is restricted to the host and other VMs running on the host, so you can reduce security for traffic on that network.

I know this is not really answering your question, but in case it is OK for you to change your setup a bit I find this topology quite suitable for VMs.

Answer 2

Your setup is somewhat complex, and it's conceivable your problem stems from a network misconfiguration. You should design and test it step by step. In the process you'll gain a deeper understanding of what goes on in your network, and you'll be able to debug errors much more effectively.

Link layer design

Make a network diagram first. Depict all VMs, computers, routers, modems, bridges, switches and their physical or logical links, which will help you identify the subnets later on. Test all physical connections. E.g. using the ip -lcommand which reports NO-CARRIER if some connection does not work, like in

1: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc [...]

Windows also reports disconnected network interface cards.

Network layer design

After having identified the subnets, assign static IP addresses and subnet masks. Static configurations are much easier to debug. Then test IP along the network links.

If a test fails, use a network analysis tool like Wireshark (available for both, Windows and Linux). As it is one possible source of error, make sure you have a basic grasp of what the address resolution protocol (ARP) does. You will see the ARP messages in wireshark.

Only after IP works along the network links, setup all static routes, and test these.