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S
TATIC
R
OUTE
C
ONFIGURATION
Introduction to Static
Route
Route
Static Route
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.
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.
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.
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.
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.
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.
reachable destinations of this router, and help troubleshooting the network.
Default Route
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.
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,
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,