This section describes both the old and new networking commands used by RHEL 6-8, you can view the current configuration by using the below command
| Current Configuration | ls -l /proc/sys/net/ipv4/conf/ |
Network Manager Command Line Interface
You can shorten many of commands by only using the first character
| General | nmcli g [status | logging | hostname | permissions] |
| Networking | nmcli n [on | off | connectivity] |
| Radio | nmcli r [all | wifi | wwan] |
| Connection | nmcli c [ show | up | down | add | modify | edit | delete | reload | load ] |
| Device | nmcli d [ status | show | connect | disconnect | delete | wifi ] |
| Agent | nmcli a [ secret | polkit | all ] |
There is a old fashioned GUI that you can use regarding the Network Manager
| Start | nmtui |
| Edit | nmtui edit <device> |
| Connection | nmtui connection <device> |
| Hostname | nmtui hostname <new hostname> |
You can configure a network interface using the ip command, but changes are not persistent across reboots; when you reboot, you will lose any changes.
| Address commands | ip addr show ip addr add <IP address> dev <device> ip addr del <IP address> dev <device> |
| Link commands | ip link show ip link set <device> up ip link set <device> down |
| Route commands | ip route show ip route add <network or host> via <gateway> dev <device> ip route del <network or host> ip route add default via <gateway> ip route replace <network or host> dev <device> ip route get <IP address> vi /etc/sysconfig/network-scripts/route-<device> |
| Neighbour Objects commands | ip neigh show show ARP ip neigh add <IP address> lladdr <mac address> dev <device> ip neigh del <IP address> dev <device> ip neigh replace <IP address> lladdr <mac address> dev <device> |
| MultiCast Address commands | ip maddr show show ARP ip maddr add <multicast address> dev <device> ip maddr del <multicast address> dev <device> |
The hostnamectl tool is provided for administering the three separate classes of host names in use on a given system.
| Hostnamectl commands | hostnamectl hostnamectl set-hostname <new hostname> hostnamectl set-hostname <name> # Set system hostname hostnamectl set-icon-name <name> # Set icon name for host hostnamectl set-chassis <name> # Set chassis type for host hostnamectl set-deployment <name> # Set deployment environment for host hostnamectl set-location <name> # Set location for host |
ss is a command-line utility that prints statistical information about sockets, allowing administrators to assess device performance over time.
| ss Commands | ss -a # Show all sockets (listening and non-listening) ss -e # Show detailed socket information ss -o # Show timer information ss -n # Do not resolve addresses ss -p # Show process using the socket ss -l # Show listening sockets ss -s # Show socket summary |
Some Introduction
| ethtool Commands | ethtool # Query or control network driver and hardware settings ethtool -g eth0 # Display ring buffer for eth0 ethtool -i eth0 # Display driver information for eth0 ethtool -p eth0 # Identify eth0 by sight, typically by causing LEDs to blink on the network port ethtool -S eth0 # Display network and driver statistics for eth0 |
ARP stands for Address Resolution Protocol, which is used to find the address of a network neighbor for a given IPv4 address.
| arp Commands | arp -a arp -v arping -I eth0 192.168.1.1 # Send ARP request to 192.168.1.1 via interface eth0 arping -D -I eth0 192.168.1.1 # Check for duplicate MAC addresses at 192.168.1.1 on eth0 |
Some Introduction
| NET-TOOLS | IPROUTE |
|---|---|
| arp -a | ip neigh |
| arp -v | ip -s neigh |
| arp -s 192.168.1.1 1:2:3:4:5:6 | ip neigh add 192.168.1.1 lladdr 1:2:3:4:5:6 dev eth1 |
| arp -i eth1 -d 192.168.1.1 | ip neigh del 192.168.1.1 dev eth1 |
| ifconfig -a | ip addr |
| ifconfig eth0 down | ip link set eth0 down |
| ifconfig eth0 up | ip link set eth0 up |
| ifconfig eth0 192.168.1.1 | ip addr add 192.168.1.1/24 dev eth0 |
| ifconfig eth0 netmask 255.255.255.0 | ip addr add 192.168.1.1/24 dev eth0 |
| ifconfig eth0 mtu 9000 | ip link set eth0 mtu 9000 |
| ifconfig eth0:0 192.168.1.2 | ip addr add 192.168.1.2/24 dev eth0 |
| netstat | ss |
| netstat -neopa | ss -neopa |
| netstat -g | ip maddr |
| route | ip route |
| route add -net 192.168.1.0 netmask 255.255.255.0 dev eth0 | ip route add 192.168.1.0/24 dev eth0 |
| route add default gw 192.168.1.1 | ip route add default via 192.168.1.1 |
Some Introduction
| Teaming Commands | nmtui # use to add new NIC's teaming, bonding, etc (GUI)
nmcli con show # list the NIC's
runner types: activebackup, loadbalance, lacp, roundrobin (example below is using loadbalance)
# create team interface (network-scripts/ifcfg-myteam0 would be created)
nmcli con add type team con-name myteam0 ifname team0 config '{ "runner": {"name": "loadbalance"}}'
nmcli con show myteam0 # show the teaming properties
nmcli con mod myteam0 team.config '{ "runner": {"name": "activebackup"}}' # change runner (or another property)
nmcli con reload # reload connection
nmcli con mod myteam0 ipv4.addresses 192.168.1.10/24 # update ifcfg-myteam0 file
nmcli con mod myteam0 ipv4.gateway 192.168.1.1
nmcli con mod myteam0 ipv4.method manual
nmcli con add type team-slave con-name team0-slave0 ifname ens224 master team0 # add ens224 interface (creates ifcfg-team0-slave0 file)
nmcli con add type team-slave con-name team0-slave1 ifname ens256 master team0 # add ens224 interface (creates ifcfg-team0-slave1 file)
nmcli connection up team0-slave0 # bring up the slave interface
nmcli connection up team0-slave1 # bring up the slave interface
nmcli con up myteam0 # display the NIC configuration
teamdctl team0 state # see the team status
teamdctl team0 config dump # dump the team configuration
teamnl team0 ports # see the team ports
teamnl team0 options # list teaming options
nmcli dev dis ens224 # disconnect a port to test teaming is working
nmcli dev con ens224 # reconnect port
nmcli con del team0-slave0 # remove the configuration (removes network-script files)
nmcli con del team0-slave1
nmcli con del myteam0 |
brctl command allows you to setup network bridging
| brctl Commands | brctl show brctl addbr br0 ifconfig ens224 0.0.0.0 down ifconfig ens256 0.0.0.0 down brctl addif br0 ens224 brctl addif br0 ens256 ifconfig ens224 up ifconfig ens256 up ifconfig br0 up |
VLANs can be setup using the below commands
| VLAN Commands | nmcli con add type vlan con-name vlan10 dev ens224 id 10 # created a ifcfg-vlan10 in network-scripts nmcli con mod vlan10 ipv4.addresses 192.168.50.181/24 # modify/add the above nmcli con mod vlan10 ipv4.gateway 192.168.50.2 nmcli con mod vlan10 ipv4.method manual nmcli con up vlan10 # start the vlan nmcli dev # confirm that the vlan is working |