I think this has been discussed elsewhere. I remember seeing this and posting before about it, I think at the time I just dropped the idea of using OMV because I couldn't be bothered and installed FreeNAS. Now I decided to try a bit harder.
Install into VirtualBox with nat network works fine.
Install into VirtualBox with bridged network does not work.
I remember when I was installing into Proxmox it wouldn't work either, but I only ever create VMs in Proxmox with bridged networking.
So there is something 'shitty' about my network, or at least there's something upsetting OMV, and it must relate to ipv6. Or so I assume.
I tried installing without configuring the network (cable unplugged), but my first attempt at this left me with no networking on boot. I wondered if I should try to 'fix' my network instead.
So I took a look at my broadband router. I've got an arrangement where I've disabled the DHCP on the router, and I run Dnsmasq for this. So the router is only ever doing routing, I control my DHPC/DNS outside of that. I don't see any ipv6 settings for DNSMasq that would make any difference here.
So I thought I would post to see if anyone has any ideas. Are there specific settings I'm looking for either on Dnsmasq or my router that I can play around with for instance?