Lesson 5

Dates: 6/12/2017
Linux networking
Linux System Administration


Exercises: Configuring Linux on a network


  • Start both, kvm3 and CentOS7 VMs: 
    virsh start kvm3
virsh start CentOS7
  • Login to console of kvm3: 
    virsh console kvm3
  • Bring up another command prompt on the desktop and login to CentOS7 
    virsh console CentOS7
  • On each VM, execute command ifconfig to read the IP address: 
    ifconfig eth0
  • Try pinging CentOS7 from kvm3 and vise versa by the IP address, for example: 
    ping -c 3 192.168.122.79
  • Become root on both the VMs 
    sudo -s

  • Reconfigure eth0 network interface on kvm3: 
    ifconfig eth0 192.168.1.5 netmask 255.255.255.0 up
  • Verify the network settings: 
    ifconfig eth0
  • Ping CentOS7 by the IP address: 
    ping -c 3 192.168.1.6
  • Try ssh to CentOS7: 
    ssh hostadm@192.168.1.6
  • Reconfigure eth0 network interface on CentOS7: 
    ifconfig eth0 192.168.1.6 netmask 255.255.255.0 up
  • Verify the network settings: 
    ifconfig eth0
  • Ping kvm3 by the IP address: 
    ping -c 3 192.168.1.5
  • Check who is login to the system: 
    who
  • Reset the network setting to the default on the both VMs: 
    ifdown eth0
ifup eth0
  • Check the updated network settings on the both VMs: 
    ifconfig eth0

    Static IP configuration on the VMs.
  • On kvm3, edit file /etc/network/interfaces and put the following settings for the static IP configuration there: 
    auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.5
netmask 255.255.255.0
  • Reset the network setting to the new default: 
    ifdown eth0
ifup eth0
  • Ping CentOS7 by the IP address: 
    ping -c 3 192.168.1.6
  • On CentOS7, edit file /etc/sysconfig/network-scripts/ifcfg-eth0 and put the following settings for the static IP configuration there: 
    DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=none
IPADDR=192.168.1.6
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
  • Reset the network setting to the new default: 
    ifdown eth0
ifup eth0
  • Ping kvm3 by the IP address: 
    ping -c 3 192.168.1.5

    • Restore the interface settings to DHCP on the both VMs.
  • On kvm3, edit file /etc/network/interfaces and put the following settings for DHCP configuration: 
    auto lo
# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp
  • Reset the network setting to the new default: 
    ifdown eth0
ifup eth0
  • Verify the network settings: 
    ifconfig eth0
  • On CentOS7, edit file /etc/sysconfig/network-scripts/ifcfg-eth0 and put the following settings for DHCP configuration: 
    NETWORKING=yes
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=dhcp
  • Reset the network setting to the new default: 
    ifdown eth0
ifup eth0
  • Verify the network settings: 
    ifconfig eth0
    The interface should acquire IP address on 192.168.122.0 network.


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