关于服务器故障的询问：https://serverfault.com/questions/706488/ubuntu-14-04-virtualbox-guest-unable-to-ping-outside-world但由于题外话，暂时搁置：
我的家庭网络上的 Ubuntu 14.04 主机上运行着一个 Ubuntu 14.04 VM，主机可以完全正常地访问网络和互联网，而客户机可以 ping 通网络上的设备并被 ping 通 - 但是它无法 ping 通（或curl）外界（即谷歌）：
ptinkler@ptinkler-dev:~$ ping www.google.com
PING www.google.com (216.58.208.68) 56(84) bytes of data.
From ptinkler-dev.home (192.168.1.75) icmp_seq=1 Destination Host Unreachable
From ptinkler-dev.home (192.168.1.75) icmp_seq=2 Destination Host Unreachable
From ptinkler-dev.home (192.168.1.75) icmp_seq=3 Destination Host Unreachable
^C
--- www.google.com ping statistics ---
4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3014ms
我已经尝试了桥接和 NAT 适配器，并且 VM 在我的工作网络上运行良好，这让我认为这可能是我的家庭网络路由器的问题。
编辑：
sysctl net.ipv4.ip_forward返回 0，但将其设置为 1 没有什么区别。
iptables -L -n -v返回：
ptinkler@ptinkler-dell-xps:~$ iptables -L -n -v
modprobe: ERROR: could not insert 'ip_tables': Operation not permitted
iptables v1.4.21: can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded
主持人：
wlan0 Link encap:Ethernet HWaddr c8:f7:33:da:68:21
inet addr:192.168.1.72 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::caf7:33ff:feda:6821/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:248973 errors:0 dropped:0 overruns:0 frame:0
TX packets:160935 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:233346198 (233.3 MB) TX bytes:22586578 (22.5 MB)
客人：
eth0 Link encap:Ethernet HWaddr 08:00:27:31:7d:f6
inet addr:192.168.1.75 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe31:7df6/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1349 errors:0 dropped:0 overruns:0 frame:0
TX packets:687 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:144462 (144.4 KB) TX bytes:50305 (50.3 KB)
Interrupt:19 Base address:0xd020