What is the default route destination?

The Default Route Destination

The default route also referred to as the default gateway, is a significant aspect of routing as well as traffic in computer networks. It means the exit or path that a host device will take in case no other path is known towards a particular destination network. Here are some key things to know about default routes and default route destinations:

Default Route is commonly referred to as the route that is automatically selected when no known route is available.

A default route is a wildcard route that is applied to forward to a specified gateway router any traffic meant for destination networks that have not been previously defined. This router then forwards the traffic in a general direction of the destination address.

As a host device such as a computer only knows directly connected networks, the default route enables the host device to forward data to other distant networks it doesn't have routes to. Without this default route being configured, any traffic that is targeted to a network that is not in its routing table would be ignored by the router.

Here, the difference between the default route and the static route is explained clearly with their respective advantages and disadvantages.

Default and static routing: Default routing and static routing are manually set routes while dynamic routing protocols like RIP or OSPF build routing tables from the network topological information. However, a key difference is: However, a key difference is:

• Static route: To match traffic for a subnet or a host, manually define which one it is and through which next hop it should be rerouted
  
• This is a gateway for all packets that are not matched by any of the other routing tables because it serves all packets with no known routing tables.

Thus, while static routes are tailored to target specific traffic, the default route targets whatever is not covered by other routes.

Default Gateway

The router interface used as the destination of the default router is called the default gateway or default router. It gets traffic that has no other particular route and guides it towards its destination.

Common examples of default gateways include:

• The internal interface of the router that is used in connecting a home or office LAN to an Internet Service Provider
  
• Specifically the virtual interface of a cloud platform's VPC router/firewall that is used by instances.

Importance of Default Routes

It is useful as it defines how packets are handled when no route is defined by routing tables that are part of the routing protocols. Without any default route in the routing table, remote traffic that does not match with configured subnet or host routing would have been discarded instead of being forwarded to the right place.

Some key benefits default routing provides include:

• Can display routing tables more simply as one route handles unknown traffic.
  
• Enables the hosts to connect easily to the internet: hosts do not require routes for numerous internet subnets
  
• Allows previously restricted or limited access to certain networks
  
• Management of the traffic and the policies from a single location through the default gateway.

Where Default Routes Terminate

The default route gateway is simply the first place packets go when they have no routing. As for where packets go after that largely depends on how that router is connected to other devices. In other cases, the forwarding path after the default gateway is based on dynamically chosen routing protocols.

Some common endpoint scenarios include: 

• An ISP router: Traffic then employs ISP core as well as Internet routing to get to the public space.
  
• Centralized VPC router: This may transmit the traffic to other subnets/instances within the given VPC.
  
• Multihomed perimeter router: When it is connected to multiple outbound paths, it can distribute the traffic load among them.

The next hop is defined from the perspective of the originating device; however, the actual routing of the traffic after that depends on the overall topology of the network.

Defining Default Route Priorities

In a network, it is possible to configure several default routes, although they have different priority levels assigned. This enables failover and redundancy to be integrated into the default routing plan by default.

The default route with the lowest administrative distance is considered to be the active default gateway on the router. However, if it does become out of service, routes with higher distance values become active depending on the priority.

The default route metrics may also be dynamically adjusted with the help of some tools, such as route maps, depending on link health and other policies. This allows very flexible traffic handling policies based on the multiple default gateways.

Implementing in End Hosts as opposed to Implementing in Routers

Default routes are applicable at the end system level like PCs and servers, and can also be set at the network level within the fabric. Routing settings define where the individual device sends its traffic which is not addressed by other routes. Default routes that are assigned in routers are used to determine how traffic will be forwarded throughout entire segments of a network.

Typical use cases include:

• End host default routes: Applied to ordinary hosts like PC, servers, etc to determine uplink to the rest of the network
  
• Interface default route: Frequently may be linked with the ISP router for WAN connection.
  
• Branch router default route: This could refer to a centralized headquarters VPN concentrator.
  
• Cloud router default route which directs the traffic between the subnets of VPC and public internet gateways.

Key Takeaways

This is because it enables the handling of traffic whose destination is unknown to be forwarded to a gateway router. This offers an important linkage that otherwise would be missing in the absence of a general/subnet-specific path for every subnet that can be created.

The definition of default routing priorities is done very carefully to get as many options for redundancy and failover as possible. By default, routers and end hosts have their default routes that offer centralized control and sophisticated guidance of packets with undefined routing table addresses.

This article further highlights the importance of understanding default route usage, behavior, and configuration towards maintaining reliable, resilient, and efficient routing in contemporary network infrastructures. In both the total connection of endend hosts and the connectivity of endtransit backbones, default routing remains relevant.