IP Command for Red Hat Enterprise Linux

In this post, we have listed some important IP commands for Red Hat Enterprise Linux.

• addr Display IP Addresses and property information
• • • ip addr – Show information for all addresses
    • ip addr show dev em1 – Display information only for device em1
• link Manage and display the state of all network interfaces
  • • ip link – Show information for all interfaces
    • ip link show dev em1 – Display information only for device em1
    • ip -s link – Display interface statistics
• route Display and alter the routing table
  • • ip route – List all of the route entries in the kernel
• maddr Manage and display multicast IP addresses
  • • ip maddr – Display multicast information for all devices
    • ip maddr show dev em1 – Display multicast information for device em1
• neigh Show neighbour objects; also known as the ARP table for IPv4
  • • ip neigh – Display neighbour objects
    • ip neigh show dev em1 – Show the ARP cache for device em1
• help Display a list of commands and arguments for each subcommand
  • • ip help – Display ip commands and arguments
    • ip addr help – Display address commands and arguments
    • ip link help – Display link commands and arguments
    • ip neigh help – Display neighbour commands and arguments

• maddr add Add a static link-layer multicast address
  • • ip maddr add 33:33:00:00:00:01 dev em1 – Add mutlicast address 33:33:00:00:00:01 to em1
• maddr del Delete a multicast address
  • ip maddr del 33:33:00:00:00:01 dev em1 – Delete address 33:33:00:00:00:01 from em1

• addr add Add an address
  • • ip addr add 192.168.1.1/24 dev em1 – Add address 192.168.1.1 with netmask 24 to device em1
• addr del Delete an address
  • • ip addr del 192.168.1.1/24 dev em1 – Remove address 192.168.1.1/24 from device em1
• link set Alter the status of the interface
  • • ip link set em1 up – Bring em1 online
    • ip link set em1 down – Bring em1 offline
    • ip link set em1 mtu 9000 – Set the MTU on em1 to 9000
    • ip link set em1 promisc on – Enable promiscuous mode for em1

• route add Add an entry to the routing table
  • • ip route add default via 192.168.1.1 dev em1 – Add a default route (for all addresses) via the local gw 192.168.1.1 that can be reached on device em1
    • ip route add 192.168.1.0/24 via 192.168.1.1 – Add a route to 192.168.1.0/24 via the gateway at 192.168.1.1
    • ip route add 192.168.1.0/24 dev em1 – Add a route to 192.168.1.0/24 that can be reached on device em1
• route delete Delete a routing table entry
  • • ip route delete 192.168.1.0/24 via 192.168.1.1 – Delete the route for 192.168.1.0/24 via the gw at 192.168.1.1
• route replace Replace, or add if not defined, a route
  • • ip route replace 192.168.1.0/24 dev em1 – Replace the defined route for 192.168.1.0/24 to use device em1
• route get Display the route an address will take
  • • ip route get 192.168.1.5 – Display the route taken for IP 192.168.1.5

• neigh add Add an entry to the ARP Table
  • • ip neigh add 192.168.1.1 lladdr 1:2:3:4:5:6 dev em1 – Add address 192.168.1.1 with MAC 1:2:3:4:5:6 to em1
• neigh del Invalidate an entry
  • • ip neigh del 192.168.1.1 dev em1 Invalidate the entry for 192.168.1.1 on em1
• neigh replace Replace, or adds if not defined, an entry to the ARP table
  • • ip neigh replace 192.168.1.1 lladdr 1:2:3:4:5:6 dev em1 – Replace the entry for address 192.168.1.1 to use MAC 1:2:3:4:5:6 on em

• arping Send ARP request to a neighbour host
  • 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
• 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
• ss Display socket statistics. The below options can be combined
  • • 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

Reference:  CHEAT SHEET for Red Hat Enterprise Linux

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