VirtualBox: MacOS host can't connect to guest, but guest can connect to host
My setup:
- MacOS host (High Sierra 10.13.3)
- Linux visit (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 IP address 10.0.2.15 and gateway 10.0.2.2. I can ping the host from the guest with no problem. However, I can't ping the guest from the 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...
The 10.0.2.2 address seems to be assigned to my host: I have a httpd server running on the host - if I navigate to 10.0.2.2 from a guest browser, I get the host's site.
Looking at the network configuration, I can'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 route 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 is understandable that the host cannot talk to the guests. The question is how can I do this?
Eventually I did figure it out. The trick is to create a host-only network, then add two network interfaces in the guest - one for the host-only network and one for using NAT. Now, the NAT interface allows the guest to access the Internet, while the host-only interface allows two-way communication between the host and the guest.