Csdrhrt

My setup:

• MacOS host (High Sierra 10.13.3)


• Linux guest (Ubuntu 16.04)


• Virtual Box 5.2.12


• NAT networking

I need to talk from host to guest and from guest to internet.

The guest gets an IP address of 10.0.2.15 and gateway of 10.0.2.2. I can ping host from guest with no problem. Yet, I cannot ping guest from host:

PING 10.0.2.15 (10.0.2.15): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
...

10.0.2.2 address seems to be assigned to my host: I have an httpd server running on host - and if I navigate to 10.0.2.2 in a browser from guest, I get the host's site.

Looking at network configuration, I don't see any interfaces added by virtualbox:

host$ ifconfig

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384

    options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>

    inet 127.0.0.1 netmask 0xff000000 

    inet6 ::1 prefixlen 128 

    inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 

    nd6 options=201<PERFORMNUD,DAD>

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

OHC4: flags=0<> mtu 0

EHC36: flags=0<> mtu 0

EHC38: flags=0<> mtu 0

OHC6: flags=0<> mtu 0

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

    ether xxxxx 

    inet6 fe80::1c34:9a51:ed93:3a5b%en1 prefixlen 64 secured scopeid 0x9 

    inet 10.37.37.37 netmask 0xffffff00 broadcast 10.37.37.255

    nd6 options=201<PERFORMNUD,DAD>

    media: autoselect

    status: active

p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304

    ether xxxxx

    media: autoselect

    status: inactive

fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078

    lladdr xxxxx

    nd6 options=201<PERFORMNUD,DAD>

    media: autoselect <full-duplex>

    status: inactive

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

    options=b<RXCSUM,TXCSUM,VLAN_HWTAGGING>

    ether xxxxx

    nd6 options=201<PERFORMNUD,DAD>

    media: autoselect (none)

    status: inactive

utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000

    inet6 fe80::9a23:8dd9:bf4e:f69d%utun0 prefixlen 64 scopeid 0x8 

    nd6 options=201<PERFORMNUD,DAD>

and I don't see any routes to connect from host to guest:

host$ netstat -nr

Routing tables



Internet:

Destination        Gateway            Flags        Refs      Use   Netif Expire

default            10.37.37.1         UGSc           77       10     en1

10.37.37/24        link#9             UCS             3        0     en1

127                127.0.0.1          UCS             0        0     lo0

127.0.0.1          127.0.0.1          UH              3   458010     lo0

169.254            link#9             UCS             0        0     en1

255.255.255.255/32 link#9             UCS             0        0     en1



Internet6:

Destination                             Gateway                         Flags         Netif Expire

default                                 fe80::%utun0                    UGcI          utun0

::1                                     ::1                             UHL             lo0

fe80::%lo0/64                           fe80::1%lo0                     UcI             lo0

fe80::1%lo0                             link#1                          UHLI            lo0

fe80::%utun0/64                         fe80::9a23:8dd9:bf4e:f69d%utun0 UcI           utun0

fe80::9a23:8dd9:bf4e:f69d%utun0         link#8                          UHLI            lo0

fe80::%en1/64                           link#9                          UCI             en1

fe80::1c34:9a51:ed93:3a5b%en1           f0:b4:79:1f:81:f0               UHLI            lo0

ff01::%lo0/32                           ::1                             UmCI            lo0

ff01::%utun0/32                         fe80::9a23:8dd9:bf4e:f69d%utun0 UmCI          utun0

ff01::%en1/32                           link#9                          UmCI            en1

ff02::%lo0/32                           ::1                             UmCI            lo0

ff02::%utun0/32                         fe80::9a23:8dd9:bf4e:f69d%utun0 UmCI          utun0

ff02::%en1/32                           link#9                          UmCI            en1

It's understandable that host can't talk to guest. The question is how can I make it do it?

I did figure it out eventually. The trick is to create a host-only network and then add two network interfaces in the guest - one for host-only network and the other one using NAT. Now the NAT interface allows the guest to access the internet and host-only interface allows two-way communication between the host and the guest.