linux_wiki:route_ip_traffic_and_create_static_routes

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Route IP Traffic And Create Static Routes

General Information

Routing IP traffic and creating static routes.


Lab Setup

The following virtual machines will be used:

  • server1.example.com (192.168.1.150) → Configure the routes here

Linux Routing

Ensure IP Forwarding is enabled if using router like functionality

# Temp Immediate Change
echo 1 > /proc/sys/net/ipv4/ip_forward
 
# Persistent Change that takes place upon system boot
vim /etc/sysctl.d/overrides.conf
 
net.ipv4.ip_forward = 1


Show Route Table

ip route show


Create static route (NOT persistent)

ip route add 216.58.217.0/24 via 192.168.1.254 dev eth1
  • 216.58.217.0/24 → destination network
  • via 192.168.1.254 → use this gateway
  • dev eth1 → use this interface


Remove static route

ip route delete 216.58.217.0/24 via 192.168.1.254 dev eth1


Creating a persistent static route.


Interface specific route using nmcli.

  • Create route
    nmcli con mod enp0s3 +ipv4.routes 216.58.219.0/24
  • Bring up the new connection config
    nmcli con up enp0s3
  • Verify route
    ip route show

  • Open nmtui
    nmtui
  • Enter on “Edit a connection”
  • Select the target network interface to use, press Enter.
    • Scroll down to “Routing”, Enter on “<Edit…>”
    • Enter on “<Add…>”
      • Type the Destination/Prefix
      • Next Hop
      • Optional Metric (default static is 0)
    • Tab to <OK> and press 'Enter'
  • Scroll to the bottom and Enter on “<OK>”
  • Tab over to <QUIT>
  • File is created at: /etc/sysconfig/network-scripts/route-<ifname>
  • Restart the network service
    systemctl restart network
  • View route
    ip route show

Note: This method is considered “legacy”, but if it works, that is all that matters on the exam.

  • Create config file
    vim /etc/sysconfig/static-routes
     
    # Minimal route entry
    any net 216.58.217.0/24 gw 192.168.1.254
     
    # Can also specify a device to use for the route
    any net 216.58.217.0/24 gw 192.168.1.254 dev eth0
     
    # Can also specify a route metric
    any net 216.58.217.0/24 gw 192.168.1.254 dev eth0 metric 110
    • any → source from any
    • net 216.58.217.0/24 → traffic to this network destination
    • gw 192.168.1.254 → use this gateway
    • OPTIONAL: dev eth0 → use this device
  • Restart the network service
    systemctl restart network
  • View route
    ip route show

  • linux_wiki/route_ip_traffic_and_create_static_routes.1525548535.txt.gz
  • Last modified: 2019/05/25 23:50
  • (external edit)