Solution: CentOS 7 network device does not start

Solution: CentOS 7 network device does not start

A new CentOS 7 system is installed in VMware 10, and no network is found when it is started, so ifconfig finds that the NIC is not started

Eno16777736: flags = 4163 <UP, BROADCAST, RUNNING, MULTICAST> mtu 1500

Ether 00: 0c: 29: 2b: c0: 1e txqueuelen 1000 (Ethernet)

RX packets 1 bytes 251 (251.0 B)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 0 bytes 0 (0.0 B)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Lo: flags = 73 <UP, LOOPBACK, RUNNING> mtu 65536

Inet 127.0.0.1 netmask 255.0.0.0

Inet6: 1 prefixlen 128 scopeid 0x10

Loop txqueuelen 0 (Local Loopback)

RX packets 386 bytes 33512 (32.7 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 386 bytes 33512 (32.7 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Habitually restart the NIC service "service network restart"

Tip:

Restarting network (via systemctl): [OK]

Restart OK ,,,,

View the NIC "ifconfig"

Still the same

Therefore, "ifup eno16777736" manually restarts the NIC.

Tip:

Connection successfully activated (D-Bus active path:/org/freedesktop/NetworkManager/ActiveConnection/0)

Started successfully

View the NIC status "ifconfig"

Eno16777736: flags = 4163 <UP, BROADCAST, RUNNING, MULTICAST> mtu 1500

Inet 192.168.41.128 netmask 255.255.255.0 broadcast 192.168.41.255

Inet6 fe80: 20c: 29ff: fe2b: c01e prefixlen 64 scopeid 0x20 <link>

Ether 00: 0c: 29: 2b: c0: 1e txqueuelen 1000 (Ethernet)

RX packets 74 bytes 9637 (9.4 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 61 bytes 7083 (6.9 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Lo: flags = 73 <UP, LOOPBACK, RUNNING> mtu 65536

Inet 127.0.0.1 netmask 255.0.0.0

Inet6: 1 prefixlen 128 scopeid 0x10

Loop txqueuelen 0 (Local Loopback)

RX packets 650 bytes 56612 (55.2 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 650 bytes 56612 (55.2 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

OK. The IP address is resolved ,,

Follow-up:

This problem does not occur originally. The main reason is that my network environment has a DHCP server, and the IP address can be automatically obtained. If you manually enter the IP address, this problem will not occur, because there is an "ONBOOT = no" in the NIC configuration file, indicating that the NIC is not activated during boot, because you are not familiar with centos7, therefore, this problem was not found.

The above solution is not thorough, because every time the server is restarted, you need to enter "ifup eno16777736", which is very troublesome, we can modify the NIC configuration file "/etc/sysconfig/network-scripts/ifcfg-eno16777736" inside the "ONBOOT = no" to "ONBOOT = yes", this problem is completely solved!