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A static route is a special route configured manually by an administrator. You can 
set up an interconnecting network with the static route configuration. The 
problem for such configuration is when a fault occurs to the network, the static 
route cannot change automatically to steer away from the node causing the fault, 
if without the help of an administrator.

In a relatively simple network, you only need to configure the static routes to make 
the router work normally. The proper configuration and usage of the static route 
can improve the network performance and ensure the bandwidth of the 
important applications.

All the following routes are static routes:

■

Reachable route: A normal route is of this type. That is, the IP packet is sent to 
the next hop via the route marked by the destination. It is a common type of 
static routes.

■

Unreachable route: When a static route to a destination has the "reject" 
attribute, all the IP packets to this destination will be discarded, and the source 
host will be informed that the destination is unreachable.

■

Blackhole route: If a static route to a destination has the "blackhole" 
attribute, the outgoing interface of this route is the Null 0 interface regardless 
of the next hop address, and any IP packets addressed to this destination are 
dropped without notifying the source host.

The attributes "reject" and "blackhole" are usually used to control the range of 
reachable destinations of this router, and help troubleshooting the network.

A default route is a special route. You can configure a default route using a static 
route. Some dynamic routing protocols can also generate default routes, such as 
OSPF and IS-IS.

In brief, a default route is used only when no suitable routing table entry is 
matched. That is, when no proper route is found, the default route is used. In a 
routing table, the default route is in the form of the route to the network 0.0.0.0 
(with the mask 0.0.0.0). You can see whether the default route has been set by 
executing the display ip routing-table command. If the destination address of a 
packet fails in matching any entry of the routing table, the router will select the 
default route to forward this packet. If there is no default route and the 
destination address of the packet fails in matching any entry in the routing table,