僅主機適配器虛擬框

我的主機是arch linux。我和客人有相同的arch linux。僅使用主機適配器和 nat 連接。在主機適配器設置中，為客人手動分配 IP。

從客人我可以訪問主機，但從主機我不能訪問客人。

主持人 - -

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

客人 - -

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

令人費解的問題，直到我注意到訪客界面統計中的一個小細節：

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

界面掛了！並且從訪客到主機的 ping 工作正常，因為 NAT 介面用於該任務……

引用自：https://serverfault.com/questions/1041377