Adicionar no arquivo da placa de rede:

ETHTOOL_OPTS="speed 100 duplex full autoneg off"

Explicacao:

Ethtool Command to Change Ethernet Adapter Settings
The ethtool -s command can be used to change the current settings by defining the values for “speed,” “duplex,” and “autoneg” in the following format

sudo ethtool -s [device_name] speed [10/100/1000] duplex [half/full] autoneg [on/off]

For example, to set the speed at 1000Mb/s, the duplex mode to ‘full’ and the auto-negotiation to ‘on’ the command would be:

sudo ethtool -s enp0s3 speed 1000 duplex full autoneg on

The ethtool [device_name] command is necessary to confirm that the changes have been applied.

Ethtool_opt Variable to Permanently Set Ethtool Command Settings
Changes made with Ethtool are by default reverted after a system is re-booted.

To apply custom settings each time a system boots edit the file for the device interface:

vi /etc/sysconfig/network-scripts/ifcfg-enp0s3

Add the desired values as a line at the end of the file using the following syntax:

ETHTOOL_OPTS="speed [100|1000|10000] duplex [half|full] autoneg [on|off]”
For example:

ETHTOOL_OPTS="speed 100 duplex full autoneg off"

Save the changes and exit the file.

Now the changes are applied after every reboot and are permanent unless the file is altered again.

Parameters

Auto
For interfaces that do autonegotiation, the appliance uses standard IEEE 802.3 autonegotiation for interface speed and direction. Preference is given to the highest speed. Preference is for full-duplex over half-duplex. This setting is the default value.
10baseT-FD
Advertises 10BASE-T PHY (10 Mbps) in full-duplex mode.
10baseT-HD
Advertises 10BASE-T PHY (10 Mbps) in half-duplex mode.
100baseTx-FD
Advertises 100BASE-TX PHY (100 Mbps) in full-duplex mode.
100baseTx-HD
Advertises 100BASE-TX PHY (100 Mbps) in half-duplex mode.
1000baseTx-FD
Advertises 1000BASE-T PHY (1 Gbps) in full-duplex mode.
10000baseTx-FD
Advertises 10000BASE-T PHY (10 Gbps) in full-duplex mode.