How a Routing Table Is Read

• Given a destination IP address, exactly one entry will be selected

• • Search for a host that matches the address
  • Search for a network that includes the address
  • • I.e., Network and netmask indicate that the address falls in their range

• Things can get complicated very quickly when multiple interfaces or routers are involved...

• • Use default route

• If more than one host or network entry matches an address, the most specific one will be chosen

• • I.e., The one with the longest netmask