Configuring A Default Route; Configuring Static Route Tracking - Cisco FirePOWER ASA 5500 series Configuration Manual

Chapter 9 Configuring IP Routing

Configuring a Default Route

A default route identifies the gateway IP address to which the security appliance sends all IP packets for
which it does not have a learned or static route. A default route is simply a static route with 0.0.0.0/0 as
the destination IP address. Routes that identify a specific destination take precedence over the default
route.
You can define up to three equal cost default route entries per device. Defining more than one equal cost
default route entry causes the traffic sent to the default route to be distributed among the specified
gateways. When defining more than one default route, you must specify the same interface for each
entry.
If you attempt to define more than three equal cost default routes, or if you attempt to define a default
route with a different interface than a previously defined default route, you receive the message
"ERROR: Cannot add route entry, possible conflict with existing routes."
You can define a separate default route for tunneled traffic along with the standard default route. When
you create a default route with the tunneled option, all encrypted traffic that arrives on the security
appliance and cannot be routed using learned or static routes is sent to this route. Otherwise, if the traffic
is not encrypted, the standard default route entry is used. You cannot define more than one default route
with the tunneled option; ECMP for tunneled traffic is not supported.
To define the default route, enter the following command:
hostname(config)# route if_name 0.0.0.0 0.0.0.0 gateway_ip [distance | tunneled]
You can enter 0 0 instead of 0.0.0.0 0.0.0.0 for the destination network address and mask, for example:
Tip
hostname(config)# route outside 0 0 192.168.1 1
The following example shows a security appliance configured with three equal cost default routes and a
default route for tunneled traffic. Unencrypted traffic received by the security appliance for which there
is no static or learned route is distributed among the gateways with the IP addresses 192.168.2.1,
192.168.2.2, 192.168.2.3. Encrypted traffic receive by the security appliance for which there is no static
or learned route is passed to the gateway with the IP address 192.168.2.4.
hostname(config)# route outside 0 0 192.168.2.1
hostname(config)# route outside 0 0 192.168.2.2
hostname(config)# route outside 0 0 192.168.2.3
hostname(config)# route outside 0 0 192.168.2.4 tunneled

Configuring Static Route Tracking

One of the problems with static routes is that there is no inherent mechanism for determining if the route
is up or down. They remain in the routing table even if the next hop gateway becomes unavailable. Static
routes are only removed from the routing table if the associated interface on the security appliance goes
down.
The static route tracking feature provides a method for tracking the availability of a static route and
installing a backup route if the primary route should fail. This allows you to, for example, define a
default route to an ISP gateway and a backup default route to a secondary ISP in case the primary ISP
becomes unavailable.
OL-10088-01
Cisco Security Appliance Command Line Configuration Guide
Configuring Static and Default Routes
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