Lesson 5

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


Exercise: Commands for Link Layer
  • On the desktop, install ethtool by using APT: 
    apt-get install ethtool
    You can see the parameter settings for the network card, such connection status, speed, duplex mode, by using command ethtool 
    ethtool enp4s0
    You can also see the driver (kernel module) attached to the network card: 
    ethtool -i enp4s0
    By using ethtool, configure the network interface for 100 MBit half-duplex, 10 MBit half-duplex modes, then autonegotiate for the default mode. 
    ethtool enp4s0
ethtool -s enp4s0 autoneg off speed 100 duplex half
ethtool enp4s0
ethtool -s enp4s0 speed 10 duplex half
ethtool enp4s0
ethtool -s enp4s0 autoneg on
ethtool -r enp4s0
ethtool enp4s0

  • ARP command: 
    arp -a
ping desktop01
ping desktop02
ping capone
arp -a
    Every time when you are trying to access any remote machine via TCP/IP, your ARP cash gets updated first, then the MAC address of the remote host, or the gateway if the host is located outside of your subnet, is used to deliver the ethernet frame.



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