#host-only network

VirtualBox has a networking mode called "host-only" which allows guests to communicate with each other, and the host to communicate with the guests. To do this, a host-only network (interface) must be defined on the host. It can be done via GUI:

or via the commandline (needs sudo because this creates a new network interface on the host): $ sudo vboxmanage hostonlyif create This creates a host-only virtual interface on the host, named vboxnetN (N starts at 0 and increments for each new one): $ ip addr list ... 12: vboxnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000     link/ether ...     inet 192.168.56.1/24 brd 192.168.56.255 scope global vboxnet0     inet6 fe80::800:27ff:fe00:0/64 scope link         valid_lft forever preferred_lft forever

There are three things to do in Shorewall: define a zone, place the host-only interface into that zone, and write a rule.

In /etc/shorewall/zones define the new zone:

# /etc/shorewall/zones #ZONE    TYPE   OPTIONS    IN                OUT#                          OPTIONS           OPTIONSvh       ipv4

In /etc/shorewall/interfaces put the host-only interface vboxnet0 in that zone:

# /etc/shorewall/interfaces

#ZONE    INTERFACE      BROADCAST    OPTIONS

vh       vboxnet0       detect       dhcp

And finally, in /etc/shorewall/rules allow all traffic in the vh zone:

# /etc/shorewall/rules

ACCEPT    vh:192.168.56.0/24    fw    all

On the guest, create a new adapter, and either use DHCP or assign it a static IP in 192.168.56.0/24 (excluding 192.168.56.1, which is the host's IP address).  Attach the adapter to the Host-only Adapter:

Or use the command line: $ vboxmanage modifyvm myguest --nic2 hostonly

Restart the shorewall service, and that should do it. Test it out by ssh'ing into the guest from the host.