重启 Ubuntu 服务器后，我无法 ping 通它。我的主机 (Herzner) 允许使用救援系统启动服务器，因此我可以访问文件系统并尝试修复它。
问题是，去哪里寻找问题？
我检查了我的 boot.log，一切看起来都很好：
cat boot.log
* Starting mDNS/DNS-SD daemon [ OK ]
* Starting bluetooth daemon [ OK ]
* Starting CUPS printing spooler/server [ OK ]
* Stopping OpenSSH server [ OK ]
* Starting OpenSSH server [ OK ]
* Starting Mount network filesystems [ OK ]
* Starting vsftpd daemon [fail]
* Starting System V initialisation compatibility [ OK ]
* Starting modem connection manager [ OK ]
* Starting configure network device security [ OK ]
* Stopping Mount network filesystems [ OK ]
* Stopping OpenSSH server [ OK ]
* Starting OpenSSH server [ OK ]
* Starting Mount network filesystems [ OK ]
* Starting vsftpd daemon [fail]
* Stopping configure virtual network devices [ OK ]
* Stopping Mount network filesystems [ OK ]
Skipping profile in /etc/apparmor.d/disable: usr.bin.firefox
Skipping profile in /etc/apparmor.d/disable: usr.sbin.rsyslogd
* Starting network connection manager [ OK ]
* Starting AppArmor profiles [ OK ]
* Loading cpufreq kernel modules... [ OK ]
* CPU0... [ OK ] * CPUFreq Utilities: Setting ondemand CPUFreq governor...
* Stopping System V initialisation compatibility [ OK ]
* Starting System V runlevel compatibility [ OK ]
* Starting anac(h)ronistic cron [ OK ]
* Starting save kernel messages [ OK ]
* Starting ACPI daemon [ OK ]
* Starting automatic crash report generation [ OK ]
* Starting regular background program processing daemon [ OK ]
* Starting deferred execution scheduler [ OK ]
* Starting LightDM Display Manager [ OK ]
* Starting CPU interrupts balancing daemon [ OK ]
* Stopping Send an event to indicate plymouth is up [ OK ]
* Stopping anac(h)ronistic cron [ OK ]
* Stopping save kernel messages [ OK ]
* Starting TeamViewer remote control daemon [ OK ]
* Starting crash report submission daemon [ OK ]