virtualbox.org

Hey, folks - first time poster here. I love VirtualBox and have found that I can do absolutely anything with it... Almost.

I'm on a Macbook running three headless instances of Ubuntu, mostly running test clusters of MySQL, Memcache, Hadoop, etc. I have them configured such that (1) they can each access the Internet (2) they can each be accessed from the Host and (3) they can each access each other. The trick to this configuration is that I can achieve (2) and (3) without having a network interface on the Host actually connected to the Internet. That is, I have each Guest configured with a Host-only network so I can achieve (2) and still log onto the boxes from the Host. I also have each Guest configured with an Internal network so they can talk to each other over a range of 10.* IPs. I work offline a lot, so achieving this setup was incredibly important.

However, in running them headless, it becomes necessary from time to time to fire up a RDP client and connect to one. So far, I've found that Microsoft Remote Desktop Connection for Mac is the only viable candidate for me. Are there any others? I can't find them.

What's horrible, and the real issue here, is that I can't seem to get MS RDC to connect unless I'm connected to the Internet. Therefor, if I don't actually have a cable plugged in, and my wireless card is inactive, I can't use MS RDC to connect to the headless instances, yet all Guest servers continue to be accessible from the others as well as from the host. When I AM connected to the Internet, I've been able to connect to them using 127.0.0.1:3389 and also 192.168.56.1:3389 (on account of the Host-only interface that's set up). However, neither work unless I have an active connection to the Internet.

This limitation seems so incredibly ridiculous that I can only assume I'm doing something completely wrong. Please help me!

I'm firing up my instances with (example Host and Port):

VBoxHeadless --startvm "MyHost" --vrdeproperty "TCP/Port"=3390

Any suggestions? Help is appreciated!

With the Host-Only adapter, the Guests can already access each other through that. So having another Internal Network adapter only adds a redundant link.

As for your issue, you have a Linux server Guest I see. Then why do you need access to the console all the time? Does it have a GUI installed? Shouldn't really help much on a server where things are generally done through CLI. With CLI only, you may just as well use SSH to connect to them. After all, you say that thanks to Host-Only, all Guests are accessible by the Host.

Sasquatch:

Thanks a bunch for your reply.

You are correct in identifying my "less-than-critical" need for a solution. I'm really just looking to solve the problem in the event that I need to access the Guests when/if SSH stops working or otherwise becomes misconfigured. Obviously, these are edge-cases, and I'm likely going to just hard kill the Guest in that case. I could get it to work while connected, so why can't I without it connected? It's more that I'd like to understand the networking at that level rather than actually put it to practical use!

Definitely not a show-stopper. Thanks again for your input.

Well, all I can say is that it's a Mac OSX issue. It would appear that it does not let applications or services list on localhost if there is no active physical connection available. The Host-Only adapter is not a physical interface, as you don't see it in System Preferences > Network. I've seen other users get bitten by OSX network woes. If the Host would be Linux or Windows, there would be no problem connecting to VRDP without an active link.

Only thing I can think of to solve this, is to always have a hard wired loopback connector with you to fool the LAN interface that there is an active link (but it will be with itself), thus giving the false impression there is an active link on it, and allow VRDP access. You can create it yourself very easily, if you have an RJ-45 connector, a tool for creating LAN cables and two coper wires from a LAN cable. Follow the instructions on Google for the proper wire connections. Or buy one online (which is a lot more expensive compared by doing it yourself if you have the tools).