我们的一台 Linux（CentOS 7.5）服务器有时无法访问。
我唯一的解决方案是systemctl restart network。
我发现我无法 ping 任何外部主机，反之亦然。
因此，我用新服务器替换了该服务器以解决此问题，但在新服务器上我遇到了同样的问题。（但我们专用网络的另一个接口始终可以访问。）
网络详细信息：
$ ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255
inet6 prefixlen 64 scopeid 0x20<link>
ether txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 8 bytes 656 (656.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
em1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet xxx.xxx.178.235 netmask 255.255.255.192 broadcast xxx.xxx.178.255
inet6 prefixlen 64 scopeid 0x20<link>
ether txqueuelen 1000 (Ethernet)
RX packets 36757565 bytes 32443194055 (30.2 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 38804620 bytes 32581348506 (30.3 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 53
em2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.11 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 prefixlen 64 scopeid 0x20<link>
ether txqueuelen 1000 (Ethernet)
RX packets 4123332 bytes 1311703055 (1.2 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3546248 bytes 510328190 (486.6 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 54
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 69896787 bytes 31178480745 (29.0 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 69896787 bytes 31178480745 (29.0 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
系统日志出奇的清晰。
除了因网络中断导致的错误外，任何日志文件似乎都没有显示任何错误。
请告诉我找出问题的最佳步骤。我已经没有任何线索了。