I am trying to set up a gateway server. Currently, I am running the thing in VirtualBox on my (strong enough) desktop PC with two network adapters.
I configured a virtual machine with two network interfaces (eth0 and eth1), both in Bridged mode. eth0 is connected to the main router going out the door (internet). eth1 is connected to a 3COM Baseline 2824-SFP Plus switch (for which documentation is hard to find). eth0 is configured to be external and has a the default gateway to 192.168.0.1.
When I configure eth1 as a normal static interface and run DHCP on the gateway server (the VM), everything works fine for PCs I connect to the switch. They can connect to the Internet and can see (ping) the server.
What I want to do, however, is create virtual LANs coming from eth1. So I set eth1 to be a Trunk port (802.1Q) and create three VLANs on eth1. These VLANs have name vlan1, vlan2 and vlan3, with the subnets configured as 192.168.1.O/24, 192.168.2.0/24 and 192.168.3.0/24. On each of these VLANs, I have a DHCP instance running to distribute addresses.
My switch is set up with port 1 to be an 'uplink' port (3COM terminology, but in the manual it says this is equal to a tagged port). Ports 2 - 8 have been assigned 'desktop' status in VLAN 1, 9 - 16 'desktop' in VLAN 2 and 17 - 24 'desktop' in VLAN 3. The gateway server is connected through the eth1 interface with port 1 of the switch.
When I plug in the client PC on one of these ports, it does not get an IP as it is supposed to.
I've been looking for the issue, but can't think of anything else than a problem with the fact that eth1 is in fact an emulated interface and the host OS strips the VLAN tags before the VM OS gets them. Anyone got an idea if this is correct?
Additionally, what seems unclear to me is the following: Is VLAN trunking always available when a (managed) switch is 802.1Q compatible?
Additional info: Host OS: Windows 8 Guest OS: Ubuntu 13.10 (x64) with Zentyal running eth1 emulation: Bridged adapter with type set to Intel PRO/1000 MT Desktop (82540EM)