No connection from host to guest (win 2012 and vb 5.0.4)

[Asiaexplorer]

Hi,

Host: Windows Server 2012 Essentials R2 and Virtual Box 5.0.4
Guest1: Ubuntu Server
Guest2: Linux Mint
Guest3: Win 7

network: bridged adapter
mainboard: ASRock C2750D4I

I can't connect to any of my guests (ping, ssh or h\ttp). Neither host to guest nor guest to host. The connection from guest to guests is possible without problems, internet connection for all guest works fine, too.
I tried static ip, with or without DHCP, nothing works.

Is there a known bug in vb 5 with windows 2012 server??

This cost me 2 days to find out, what's the problem... Now I am back to 4.3.30 and it's working again without any problems... So annoying!

Thanks in advance!

[noteirak]

Yes this is a known issue, see Ticket #14457 - cannot ping host <--> VMs after upgrade to VirtualBox 5.0.x with NDIS6 driver.
A workaround is also given in the ticket.