Discussion

Table 9-3. General actions to take on matching routes
Action term Description Additional action taken
accept Accept the route and propagate it. Evaluation of the policy statement ends. If the policy has
more terms, they are ignored. If the policy is part of a chain
of policies, any subsequent policies are ignored.
reject Reject the route and do not propagate it. Evaluation of the policy statement ends. If the policy has
more terms, they are ignored. If the policy is part of a chain
of policies, any subsequent policies are ignored.
next term Take any actions in the then clause that
modify the route properties.
Any accept or reject action is ignored, and evaluation of the
policy statement jumps to the next term in the policy.
next policy
Take any actions in the then clause that
modify the route properties.
Because the policy in this recipe has one term, if the packet matches all the conditions
(similar to a logical AND action), the action is taken. If there are no actions or
if a route does not match all the conditions, the default accept or reject action is
taken, which for OSPF is to reject the route and not advertise it. If a routing policy
has multiple terms, they are evaluated sequentially. As soon as the route matches a
term, the action in that term is taken and policy evaluation completes. If the route
does not match any of the terms, the default action for that protocol is taken.
The then clause can include additional actions that modify the route properties.
These are discussed in Recipe 9.2.
The third command in the recipe, set export send-statics, applies the policy to
OSPF, referencing it by name. The set export command affects routes that OSPF
advertises to its peers. By default, OSPF advertises only routes learned from other
OSPF routers. This policy configures OSPF to also advertise any static routes configured
on the local router.
Use the show policy command to see which policies are configured:
aviva@router1> show policy
Configured policies:
send-statics
Any accept or reject action is ignored, any subsequent
terms in the policy are ignored, and evaluation of the policy
statement jumps to the next policy in the chain.
For just one policy, the output is not very interesting. However, if the configuration
contains a number of routing policies, this command is a good way to get a quick list
of the policies.
Because all routing policies are in a common place in the configuration (in the [edit
policy-options] hierarchy), you can refer to them more than once when configuring
a routing protocol. For example, you can use the policy in this recipe to redistribute
static routes into an EBGP group. Because the policy is already defined, you need to
just reference the EBGP group:
288 | Chapter 9: Routing Policy and Firewall Filters
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