Host only adapter virtual box

My host is arch linux. And i have the same arch linux as guest. Host only adapter and nat connections are used. In host adapter settings manual assignment of ip is done for the guests.

From the guest i can access the host but from the host i cannot access the guest.

Host ---

ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp1s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 20:1a:06:1f:b7:ad brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether f8:2f:a8:ed:d7:a5 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.6/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp2s0
       valid_lft 83103sec preferred_lft 83103sec
    inet6 fe80::b2d9:237f:aec4:181/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
10: vboxnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 0a:00:27:00:00:00 brd ff:ff:ff:ff:ff:ff
    inet 192.168.56.1/24 brd 192.168.56.255 scope global vboxnet0
       valid_lft forever preferred_lft forever
    inet6 fe80::800:27ff:fe00:0/64 scope link 
       valid_lft forever preferred_lft forever

ping 192.168.56.8                                                                                                                           3s
PING 192.168.56.8 (192.168.56.8) 56(84) bytes of data.
From 192.168.56.1 icmp_seq=1 Destination Host Unreachable
From 192.168.56.1 icmp_seq=2 Destination Host Unreachable
From 192.168.56.1 icmp_seq=3 Destination Host Unreachable
^C
--- 192.168.56.8 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4123ms

Guest ---

ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 08:00:27:04:81:09 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global dynamic noprefixroute enp0s3
       valid_lft 83209sec preferred_lft 83209sec
    inet6 fe80::ebdc:629a:ea5:dc7a/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: enp0s8: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 08:00:27:ed:d3:c9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.56.8/24 brd 192.168.56.255 scope global enp0s8
       valid_lft forever preferred_lft forever

ping 192.168.56.1

PING 192.168.56.1 (192.168.56.1) 56(84) bytes of data.
64 bytes from 192.168.56.1: icmp_seq=1 ttl=63 time=0.512 ms
64 bytes from 192.168.56.1: icmp_seq=2 ttl=63 time=0.560 ms
64 bytes from 192.168.56.1: icmp_seq=3 ttl=63 time=0.474 ms
^C
--- 192.168.56.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2032ms
rtt min/avg/max/mdev = 0.474/0.515/0.560/0.035 ms

Solution 1:

Puzzling question, until I noticed a small detail in the interface statistics of the guest:

3: enp0s8: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000

The interface is down! And the ping from the guest to the host works, because the NAT interface is used for that task...