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RHEL Networking

This is based on RHEL 7,8, and 9.

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systemctl enable network            # does this exist?
/etc/init.d/network            # does this exist?

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Format for network configuration files:

/etc/NetworkManager/ VPN, mobile, PPPoE
/etc/sysconfig/ most network config info
/etc/sysconfig/network-scripts/  
/etc/sysconfig/network  
/etc/NetworkManager/system-connections/ net manager configs go here
/run/NetworkManager/system-connections/ temporary until reboot
/usr/lib/NetworkManager/system-connections/ default uneditable

Load config file into Network Manager:


nmcli connection load /etc/sysconfig/network-scripts/ifcfg-connection_name

Static interfaces with ifcfg format:

/etc/sysconfig/network-scripts/ifcfg-enp1s0
DEVICE=enp1s0 BOOTPROTO=none ONBOOT=yes PREFIX=24 IPADDR=10.0.1.27 GATEWAY=10.0.1.1

Using IPv6:

/etc/sysconfig/network-scripts/ifcfg-enp1s0
DEVICE=enp1s0 BOOTPROTO=none ONBOOT=yes IPV6INIT=yes IPV6ADDR=2001:db8:1::2/64

Using DHCP:

/etc/sysconfig/network-scripts/ifcfg-enp1s0
DEVICE=enp1s0 BOOTPROTO=dhcp ONBOOT=yes

Pass specific hostname to DHCP server ( only use one of these ):


DHCP_HOSTNAME=hostname
DHCP_FQDN=fully.qualified.domain.name

Use specific DNS servers:


PEERDNS=no
DNS1=ip-address
DNS2=ip-address

Key file format example:


[connection]
id=example_connection
type=802-3-ethernet
autoconnect=true

[ipv4]
method=auto

[ipv6]
method=auto

[802-3-ethernet]
mac-address=00:53:00:8f:fa:66

!!!!!! need static example !!!!!!1


chown root:root /etc/NetworkManager/system-connections/example.nmconnection
chmod 600 /etc/NetworkManager/system-connections/example.nmconnection
nmcli connection reload               # reload profile
nmcli -f NAME,UUID,FILENAME connection   # verify

Check connection status:


nmcli connection show
nmcli connection show enp1s0
nmcli device status

Add connection and modify it with nmcli:


nmcli connection add con-name Example-Connection ifname enp7s0 type ethernet
nmcli connection modify Example-Connection ipv4.addresses 192.0.2.1/24
nmcli connection modify Example-Connection ipv6.addresses 2001:db8:1::1/64
nmcli connection modify Example-Connection ipv4.method manual
nmcli connection modify Example-Connection ipv6.method manual
nmcli connection modify Example-Connection ipv4.gateway 192.0.2.254
nmcli connection modify Example-Connection ipv6.gateway 2001:db8:1::fffe
nmcli connection modify Example-Connection ipv4.dns "192.0.2.200"
nmcli connection modify Example-Connection ipv6.dns "2001:db8:1::ffbb"
nmcli connection modify Example-Connection ipv4.dns-search example.com
nmcli connection modify Example-Connection ipv6.dns-search example.com
sudo nmcli connection modify enp1s0 +ipv4.routes "192.0.2.0/24 198.51.100.1"
sudo nmcli connection up enp1s0
sudo nmcli connection down enp1s0

Load new config into network manager:


nmcli connection load /etc/sysconfig/network-scripts/ifcfg-connection_name

Update existing network manager config:


nmcli connection up connection_name

Set unmanaged devices:

/etc/NetworkManager/conf.d/99-unmanaged-devices.conf
[keyfile] unmanaged-devices=interface-name:enp1s0;enp1s1

Reload Network Manager and check status:


systemctl reload NetworkManager
nmcli device status

Save and load configuration:


nmstatectl show enp1s0 > ~/network-config.yml    # save current state to a config file
nmstatectl apply ~/network-config.yml            # load state from config file

RHEL DNS

/etc/resolv.conf # configured by network manager based on interface configs /etc/NetworkManager/NetworkManager.conf # set DNS priority for interfaces here

Disable using NetworkManager for DNS so that it won’t overwrite /etc/resolv.conf:

/etc/NetworkManager/conf.d/90-dns-none.conf [main] dns=none

systemctl reload NetworkManager

Also, if /etc/resolv.conf is a symlink, it won’t be overwritten by

RHEL 8 WIFI


nmcli radio wifi on          # turn radio on
nmcli radio wifi off         # turn radio off
nmcli device wifi rescan     # refresh
nmcli dev wifi list          # view APs
nmcli dev wifi connect MyCafe password wireless-password            # connect
nmcli dev wifi connect MyCafe password wireless_password hidden yes # connect to hidden network

nmcli con add con-name MyCafe ifname wlan0 type wifi ssid MyCafe ` `ip4 192.168.100.101/24 gw4 192.168.100.1
nmcli con modify con-name MyCafe ipv4.dns "192.160.100.1"
nmcli con modify con-name MyCafe ipv4.dns-search "example.com"

Other RHEL Network Topics:

References