Networking: Understanding Routing Tables

Viewing Routing Table

• The netstat -r command displays the routing table, including the destination, gateway, netmask, and interface.
• The ip route command shows the routing table in a similar format, with additional information about the protocol and scope.
• The route command is similar to netstat -r, but with additional information about the metric and reference count.

IPv6 Routing Table

• The route -6, netstat -6r, and ip -6 route commands display the IPv6 routing table.
• The IPv6 routing table includes information about the destination, next hop, flag, metric, reference count, and use.

Flags in Routing Table

• The U flag indicates that a route is up.
• The ! flag indicates a rejected route.
• The n flag indicates that the route has not been cached.
• The G flag indicates a gateway.

Adding and Deleting Routes

• The route -6 add command adds a new route to the IPv6 routing table.
• The ip route add command adds a new route to the IPv6 routing table.
• The route -6 del command deletes a route from the IPv6 routing table.
• The ip route del command deletes a route from the IPv6 routing table.

Ping Command

• The ping6 command is used to test IPv6 connectivity.
• The ping6 command can be used to test the reachability of an IPv6 address.