Snow Leopard Server "invalid serial number" due to bridged ethernet

Make sure your bridged network is configured properly. You could have a DNS or security configuration problem that is preventing your server from reaching Apple's validation server.

The "duplicate detected" error would suggest that it is seeing both the VM and the actual server as having the same serial number. That might indicate either a problem with the VM configuration or an incompatibility between Virtual Box and Snow Leopard Server, or possibly that both the VM and the server have the same local IP address, which would be problematic. You might want to check the Virtual Box forums and see if others have the same issue

You might also try is setting static IP addresses in the router for the server MAC address and the VM MAC address to make sure that they are not being assigned the same DHCP IP address.

You'll want to figure out why you have both 10.0.2.2 and 192.168.1.113 addresses here for the same host (and particularly where the host doesn't know about the second and separate subnet as "itself"); that's incorrect, and that's the likely trigger. I'm guessing there's NAT here, and NAT gets ugly in general.

This isn't so much a problem with Apple's serial number licensing, it's with the disparate addressing configuration combined with a NAT "device" that's also passing Ethernet multicasts. Taken together, you're seeing exactly what is expected with that. The OS X Server licensing is doing exactly what it should be doing.

What's happening is that the network configuration error here means that OS X Server is detecting itself via a typical Ethernet multicast, and with a different NAT'd address that it doesn't recognize as its own; as being itself, via a NAT. Other stuff that uses Ethernet multicasts, too, so protocols including Bonjour will likely be cranky within this configuration, too. DNS, as was mentioned earlier, must also be configured for this; if you have a host with its own self-IP and visibility to a NAT'd IP visible, then DNS will get cranky. Security, too, will get cranky when DNS is cranky. And Open Directory, being based on DNS and IP and security, will very likely get confounded, too.

You can either block the Ethernet multicasts from crossing at the NAT device (which is what a NAT firewall does), or can switch to a routed network configuration and get rid of NAT (which is what a router and IP subnet routing does).

And irrespective of the rest of the discussion around licensing and multicasts, having anything in 192.168.1.0/24 is a bit messy, if you're planning on getting VPNs involved. Using another subnet (in this case) within the 10.0.0.0/8 block would be a better choice, rather than 192.168.0.0/24 or 192.168.1.0/24 subnets.

Where is the bridge in your network? Do you have a router ahead of the server in bridge mode with the server doing the local routing? Are the server DNS settings configured correctly? Are the server and the VM on the same subnet?

By the way, "unlimited client serial number," means that the server can have unlimited clients (as opposed to 10 or 100 or unlimited the way Plesk is licensed), but it doesn't mean that you can have unlimited servers with the same license number. If you have another installation of OS X server running in the VM with the same license number, that could be the source of the trouble.

As a further follow-up, the techinical document you referenced in your opening post refers to a problem that occurs with OS X server running with multiple network interfaces, but it is not likely relevant in cases where multiple servers are running in a VM, if that's what you are trying to accomplish.

I would say that if the multiple servers are all using the same license key, then that is where your problem lies. Unlimited clients means that a server can host services for unlimited clients, but it doesn't mean you can run multiple servers from the same key.

MacSter2008 wrote:

Perhaps the Multiple Servers using the same license key is the problem.

However according to Apple I am indeed allowed to use multiple servers from the same key.

The article you have referred to deals with running OS X server on a machine with multiple network interfaces, as on a Mac Pro with two Ethernet NICS. That is an entirely different issue than actually running multiple servers.

I suspect the duplicate key error message is a result of the validation server detecting multiple servers online using the same key. You may need to contact Apple support on this and have them confirm whether or not you can run multiple servers in a VM using the same license key. You may need a special license key apart from the one that came with the server software to do what you are attempting.

You really do have more than one server, and whether OS X Server is running as a guest or as a base system?

If so, you need a different license key for each.

I'm not aware of any commercially-licensed (and virtual-capable) server operating system that allows "free guests", for that matter. This isn't particularly unique.

-- other comments --

Unrelated to the OS X Server licensing, and from this statement: "DNS must be configured correctly for the real computer and any others on the linksys...", you can then switch that phrasing from "must be" to "is" by launching Terminal.app and issue the following non-destructive command:

sudo changeip -checkhostname

That will indicate that DNS is correct and valid and no changes are required, or that there are errors and changes are required. Invalid DNS configurations are surprisingly common, in my experience.

Whether or not your Linksys allows only 192.168.1.0/24 is irrelevent to whether VPNs will operate here or not; if both ends of the VPN are in 192.168.1.0/24, then IP routing will not work, and the VPN will not be established. As a potential option, re-flash that Linksys with DD-WRT or other such software, if your particular model allows that. Or get an old PC with two NICs, and load and configure it with one of the various open-source firewall packages around. Or get a server-grade (commercial) firewall.

MrHoffman wrote:

You really do have more than one server, and whether OS X Server is running as a guest or as a base system?

The OP appears to be confused over the issue of running a single server with multiple NICs and running multiple servers. These issues are not related.

If he's running SLS in a VM within the original installation then he is running more than one server, thus the duplicate license error. It is extremely unlikely that Apple allows multiple installations of its OS to be run on the same license key, and therein lies the problem. He needs what would essentially be considered an enterprise license, and I don't know if Apple provides such a license. I doubt that the OP's problem is a DNS issue based on the information he has provided.

Thank you capaho, though you appear to be confused over what I am seeking, or the phrasing of my question (to the OP) was unclear. I am aware of what you are writing (both in terms of the VM and the licensing), and am seeking confirmation that the OP is actually running multiple instances of the same license key.

The DNS information was strictly as an extra comment, and was inferring from past similar questions and particularly from the phrasing OP used in the postings - DNS configuration errors can and have arisen in similar cases. Failure to have proper DNS services on a NAT'd network (which commonly arises inside a VM, as well as within a more typical gateway'd network) also causes various weird problems with OS X Server, whether within a VM or not.

My apologies on my confusing phrasing.