Host-only network: Guest -> Host communication fails when host connected to 192x168.X.X IP-network

[Lassi]

Configured a home box router with similar kind of IP-network configuration that our RD-network has. And the router also serves IP addresses to the PC from the same address space, using DHCP.

Router LAN configuration: Net: 192.168.100.0 Subnet Mask: 255.255.224.0 Default Gateway: 192.168.100.1

VirtualBox Host-Only network adapter: IPv4 Address. . . . . . . . . . . : 172.16.0.1 Subnet Mask . . . . . . . . . . . : 255.240.0.0 (DHCP or manual IP address configuration on Guest OS)

Host OS: Windows 10 Guest OS: Ubuntu 18.04

Steps to reproduce:

1. Configure router and VirtualBox
2. Connect to router
3. Disable Windows 10 firewall (to allow ICMP)
4. Observe that given network configurations are applied on host and guest (ipconfig /all, ifconfig)
5. Ping the host-only interface from Guest OS: 'ping 172.16.0.1'

Expected result: Ping successful

Actual: Ping fails

Extensive discussion in the forum: ​https://forums.virtualbox.org/viewtopic.php?f=6&t=94323&start=15

[Lassi]

Any 192.168.*.* IP-network for host cable connection will do to reproduce this, apparently... Verified verified with the default config of the router, 192.168.1.0 / 24.

[Socratis]

Related discussion in the forums: ​https://forums.virtualbox.org/viewtopic.php?f=6&t=94323

[Lassi]

Got solved by firewall policies change. Older policy was silent when dropping inbound connnections.

Closing as invalid.

[Valery Ushakov]

Thanks for the update.