Ubuntu/Linux 网络问题处理总结

学习和工作中，总是遇到奇奇怪怪的一些问题，处理之后记录在这里。

一、由于网卡名改变导致的网络服务启动失败
1.现象：服务器重启之后发现网络不通，然后ifconfig 发现网卡eth0不见了，只有本地lo

lo        Link encap:Local Loopback  
inet addr:127.0.0.1  Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING  MTU:12536  Metric:1
RX packets:6 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1 
RX bytes:594 (594.0 B)  TX bytes:594 (594.0 B)

然后尝试了ifup eth0，返回结果说没有这个设备
然后重启网络服务/etc/init.d/networking restart也是失败的

Restarting networking (via systemctl): networking.serviceJob for networking.service failed because the control process exited with error code. See "systemctl status networking.service" and "journalctl -xe" for details.
 failed!

查状态/etc/init.d/networking status出现错误：Failed to start Raise network interf….
2.检查网卡名dmesg |grep eth

[    0.000000] psci: probing for conduit method from ACPI.
[   xx.2xxx25] netif_napi_add() called with weight 256 on device eth%d
[   xx.1xxx76] r8169 xxx:03 enp2s3: renamed from eth3
[   xx.2xxx12] r8169 xxx:01 enp2s1: renamed from eth1
[   xx.2xxx71] r8169 xxx:02 enp2s2: renamed from eth2
[   xx.3xxx96] r8169 xxx:00 enp2s0: renamed from eth0

发现网卡名发生变化
4.修改网络配置文件：
vim /etc/network/interfaces
将里面的eth0都替换成新网卡名：enp2s0

auto enp2s0
iface enp2s0 inet static
address 192.168.5.39
gateway 192.168.5.1
netmask 255.255.255.0