How a Host Routes

How a Host Routes

1. Host Forwarding Decision

   • Routing Table
   • Send Packets:
     • Itself
       • "127.0.0.1" IPv4 "::1" IPv6
     • Local Host
       • Source and destination on same network address
     • Remote Host
       • Source or destination not on same network addresses
   • Source End Device determimes if destination IP address are on same network
     • IPv4
       • Uses own Subnet mask, IPv4 address of own and destination
     • IPv6
       • Local router advertises local network address to all devices on the network

2. Default Gateway

   • Network device that can route traffic to other networks
   • Features:
     • Has local IP address, in same address range
     • Can accept data into local network and forward data out of local network
     • Routes traffic to other networks
   • Required to send trafic outside local network
   • No default gateway/not configured/ is down, no forwarding outside local network

3. A Host Routes to the Default Gateway

   • Host route usually includes a default gateway
   • IPv4
     • Recieves address of default gateway either dynamically or manually
   • IPv6
     • Router advertises the default gateway or host configured manually
   • Default gateway ---> default route
     • Default route
       • Route or pathway the pc uses to contact a remote network

4. Host Routing Tables

   • "route print" or "netstar -r" on cmd
   • Only display IPv4 route table
   • Sections using "netstat -r":
     • Interface List
       • Lists MAC addresses
       • Assigned interface number
         • Includes Ethernet, Wi-fi, bluetooth
     • IPv4 Route Table
       • Lists all known IPv4 routes
         • Including direct connections, local network and local default routes
     • IPv6 Route Table
       • Lists all known IPv6 routes
         • Including direct connections, local network and local default routes