O CentOS 7 não consegue obter o endereço IPv4 do servidor DHCP

Question

Tenho uma sala de aula cheia de computadores rodando o CentOS 7 e apenas um computador não consegue obter o endereço IPv4 do servidor DHCP durante a inicialização, porque a NIC ainda não está ativa, quando o cliente dhcp tenta obter o endereço IPv4 do servidor DHCP. Aqui está a saída de / var / log / messages:

Oct 14 14:15:03 a302 network: [  OK  ]
Oct 14 14:15:03 a302 network: Activating interface enp0s25:
Oct 14 14:15:04 a302 kernel: IPv6: ADDRCONF(NETDEV_UP): enp0s25: link is not ready
...
Oct 14 14:15:09 a302 network: Determining IP information for enp0s25 ... failed; missing links. Is the cable OK?
Oct 14 14:15:09 a302 network: [FAILED]

Quando a NIC fica pronta, ela recebe pelo menos o endereço IPv6:

Oct 14 14:15:19 a302 kernel: e1000e: enp0s25 NIC Link is Up 100 Mbps Full Duplex, Flow Control: None
Oct 14 14:15:19 a302 kernel: e1000e 0000:00:19.0 enp0s25: Link Speed was downgraded by SmartSpeed
Oct 14 14:15:19 a302 kernel: e1000e 0000:00:19.0 enp0s25: 10/100 speed: disabling TSO
Oct 14 14:15:19 a302 kernel: IPv6: ADDRCONF(NETDEV_CHANGE): enp0s25: link becomes ready
Oct 14 14:15:19 a302 NetworkManager[938]: <info> (enp0s25): link connected
Oct 14 14:15:20 a302 avahi-daemon[770]: Registering new address record for fe80::223:aeff:fea4:76d3 on enp0s25.*.
Oct 14 14:15:21 a302 avahi-daemon[770]: Registering new address record for 2001:718:1c01:72:223:aeff:fea4:76d3 on enp0s25.*.
Oct 14 14:15:21 a302 avahi-daemon[770]: Withdrawing address record for fe80::223:aeff:fea4:76d3 on enp0s25.

O conteúdo de / etc / sysconfig / network-scripts / ifcfg-enp0s25 é o seguinte:

# Generated by dracut initrd
DEVICE="enp0s25"
ONBOOT=yes
NETBOOT=yes
UUID="c2ed9174-ece7-4bea-9da4-0123456789ab"
IPV6INIT=yes
BOOTPROTO=dhcp
HWADDR="00:23:ae:11:22:33"
TYPE=Ethernet
NAME="enp0s25"
NM_CONTROLLED=no
IPV4_FAILURE_FATAL=yes

Outros computadores em sala de aula obtêm endereços IPv4 sem nenhum problema.

Editar: problema estava no cabo UTP. Havia um par de fios errados.