[j-nsp] Testing a new BGP Policy Statement before applying

[Chuck Anderson]

On Sat, Oct 10, 2009 at 09:08:40PM +0200, Jason Alex wrote:
> Dear All,
>             I have configured a new Policy statement in my configuration , i
> want to test it in the current routing table before applying it to a BGP
> Peer as an export policy
> 
> In cisco you can test a route-map before applying it using the below command
> 
> "show ip bgp route-map "
> 
> Is there is any similar command in JUNOS

Yes, "test policy".  Keep in mind that different protocols have 
different default policies that get applied if the prefix doesn't 
match the configured policy.  For BGP this is accept, but for RIP it 
is reject.  "test policy" always uses accept as the default policy, so 
unless you explicitly reject all routes that you don't want to match 
in your policy you will see more routes matching than you want.

http://www.juniper.net/techpubs/en_US/junos9.6/information-products/topic-collections/config-guide-policy/policy-protocol-import-export-defaults.html#id-10113228

http://www.juniper.net/techpubs/en_US/junos9.6/information-products/topic-collections/config-guide-policy/policy-routing-policies-tests.html#id-10144672

It is unfortunate that you cannot test policy chains.  I always use a 
REJECT policy as the last policy in my policy chains rather than build 
the reject into a single policy, which basically makes "test policy" 
useless for me.  If chains were accepted, you could test them like 
this:

test policy [ EGBP-IN REJECT ]

where EBGP-IN doesn't have any explicit "then reject" statements.