5-2 Configure Networking and Hostname Resolution Statically or Dynamically: Network Manager

Question 1

/etc/sysconfig/network-scripts

ex:
cat /etc/sysconfig/network-scripts/ifcfg-eth0

Answer 1

Location of all configuration files for network cards, etc.

Each connection to system is a configuration, each configuration is attached to a device, each device has a configuration file

ex: for eth0

Question 2

ls /sys/class/net

nmcli dev status

Answer 2

2 ways to

View which network cards are attached to the system, or to list all the devices.

Question 3

Display a list of connections

Answer 3

nmcli con show

Question 4

Display “device” status

Answer 4

nmcli dev status

Question 5

Display help for adding connections

Answer 5

nmcli con add help

Question 6

Add a connection

Answer 6

nmcli con add con-name
“nameofthecon” type ethernet ifname eth0

ifname is the name of the Ethernet device; can find them by doing ls /sys/class/net
By not specifying a gateway or IP, the connection will attempt to go with DHCP

nmcli con add con-name “nameofthecon”
ifname eth0 autoconnect no type Ethernet ip4 ipaddress gw4 gateway

autoconnect will automatically bring up the network connection when the system starts

Question 7

Modify an existing network connection

ex:

Answer 7

nmcli con mod “nameofthecon”

ex:
nmcli con mod “nameofthecon” connection.autocorrect yes

cat /etc/sysconfig/network-scripts/ifcfg-nameofthecon
see if ONBOOT=yes, which means this configuration will automatically connect. if device set to DEVICE=eth0, it will connect to configuration to eth0 device

Press tab twice for auto complete to show options

Question 8

After modifying a network connection, you should reload the configuration

Answer 8

nmcli con reload

Question 9

List all devices

Answer 9

nmcli dev status

Question 10

Turn off a network device

Answer 10

nmcli dev disconnect “device”

Question 11

Turn on a network device

Answer 11

nmcli dev connect “device”

Question 12

List all connections (connections are con gurations that are attached to a device)

Answer 12

nmcli con show

Question 13

Activate or “bring up” a connection

Answer 13

nmcli con up “connectionname”

Question 14

Deactivate or “bring down” a connection

Answer 14

nmcli con down “connectionname”

Question 15

Delete a connection

Answer 15

nmcli con del “connectionname”

Question 16

Change the method from static IP to DHCP

Answer 16

nmcli con mod “con-name ipv4.method manual

Question 17

Example: Add static IP address to eno1 with an IP of 192.168.122.5/24 and gateway of 192.168.1.1

Answer 17

nmcli con mod eno1 ipv4.addresses “192.168.122.5/24 192.168.1.1”

Question 18

nm-connection-manager

Answer 18

GUI interface to manage connections

Question 19

nm (press tab twice)

Answer 19

to see commands that start with nm

Question 20

nmtui

Answer 20

network manager text based gui to configure networking

Question 21

nmcli con show –active

Answer 21

to display only active connections

Question 22

nmcli con show “con-name”

Answer 22

to show a connection by name

Question 23

dhcp vs static

Answer 23

static means manually configured

dhcp means the device is configured to find dhcp server to get its ip automatically assigned

these can be configuration differences on diff connection configuration files. Can be diff connections for same device, where connections can be switched between

Question 24

See if a device is connected

Answer 24

nmcli dev show

Connected device has GENERAL.STATE has a (connected) value

Question 25

How to see if a connection’s configuration is dhcp?

Answer 25

Inside /etc/sysconfig/network-scripts/ifcfg-nameofconnection

BOOTPROTO=dhcp

Question 26

Start and Stop Network Manager

Answer 26

systemctl start NetworkManager
systemctl enable NetworkManager
systemctl restart network

If you get lost, use the man page for nmcli-examples to help when configuring nmcli