Routing

Hi there i have the following topology

RouterA connected to RouterB and I want to run ospf.

RouterA is an ABR

 

RouterA@yyyy> show configuration protocols ospf
area 0.0.1.94 {
nssa {
default-lsa {
default-metric 10;
type-7;
}
no-summaries;
}
interface xe-1/1/10:0.350 {
priority 150;
hello-interval 2;
dead-interval 8;
authentication {
md5 1 key "xxxxxx"; ## SECRET-DATA
}
}
}
area 0.0.0.0 {
interface lo0.0 {
passive;
}
}

and

RouterB@xxx> show configuration protocols ospf
area 0.0.1.94 {
nssa;
interface vlan.350 {
priority 100;
hello-interval 2;
dead-interval 8;
authentication {
md5 1 key "xxxxxx"; ## SECRET-DATA
}
}
interface lo0.0 {
passive;
}
interface vlan.2001 {
passive;
}
}

Router A learn via BGP the default route from upstream

RouterA@yyyy> > show route 0.0.0.0

inet.0: 10792 destinations, 20875 routes (10767 active, 0 holddown, 25 hidden)
+ = Active Route, - = Last Active, * = Both

0.0.0.0/0 *[BGP/170] 00:15:30, localpref 100
AS path: xxxx, validation-state: unverified
> to yyyy via ae0.0

 

But RouterB dose not receive any default-route. Why?

RouterB@xxx>> show route protocol ospf

inet.0: 15 destinations, 15 routes (15 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

224.0.0.5/32 *[OSPF/10] 192w1d 00:27:39, metric 1
MultiRecv

 

OSPF peering is ok and on RouterA I am able to see via ospf the directly connected routes of RouterB.

Hello

 

Try removing type-7 on your nssa default-lsa configuration

Router A should have a ospf adjacency in area 0 to advertise default route.

Thnaks for the answer.

Basically based on this thread

https://www.reddit.com/r/Juniper/comments/3xvncq/totally_stubby_area_not_sending_default_route_on/

it seems that

“Area 0 must have a neighbor to announce a default route into stub or totally stubby areas”

 

But I am working with nssa area first point.

 

More, I do not really need an ospf area 0 (I know is needed for different reason in theory) and I apply the follwoing workaround

On RouterA I change the config:

1)I eliminate the area 0.0.0.0

2)I apply an export policy to export the default route

3)Now i have

set protocols ospf export accept-default
set protocols ospf no-active-backbone
set protocols ospf area 0.0.1.94 nssa default-lsa default-metric 10
set protocols ospf area 0.0.1.94 nssa default-lsa type-7
set protocols ospf area 0.0.1.94 nssa no-summaries
set protocols ospf area 0.0.1.94 interface xe-1/1/10:0.350 priority 150
set protocols ospf area 0.0.1.94 interface xe-1/1/10:0.350 hello-interval 2
set protocols ospf area 0.0.1.94 interface xe-1/1/10:0.350 dead-interval 8
set protocols ospf area 0.0.1.94 interface xe-1/1/10:0.350 authentication md5 1 key "xxxx"

 

And on router B now i have the default-route but I really did not understand the effect of the commands.

• set protocols ospf no-active-backbone : ignore the junos mechanism to stop adevrtising default-route in case of loss connection from backbone
  
• set protocols ospf area 0.0.1.94 nssa default-lsa default-metric 10
  set protocols ospf area 0.0.1.94 nssa default-lsa type-7
  set protocols ospf area 0.0.1.94 nssa no-summaries

The above 3 commands should take care to inject default-route. But does not work. To have it working I need to add the export policy

set policy-options policy-statement accept-default term yes from route-filter 0.0.0.0/0 exact
set policy-options policy-statement accept-default term yes then accept

 

and apply it to ospf

set protocols ospf export accept-default

 

Which in my opinion should not be the case. Protocol should work without this export policy. What do you think?

You are correct. You don't need export policy to get 0/0 advertised on totally nssa. Your configuration looks correct though

 

Here I want to point out something:

1. On ROUTER A, You don't need to care about 0/0. No matter it has 0/0 or not in its RIB, it's going to generate 0/0 in LSDB

2. Check on ROUTER B, "show ospf database" and see if you can see 0/0 entry if you don't have export policy on router A

Now  I have the issue and can't figure it out.
I posted here to look for any insights.

I appreciate your ideas if you have for this.

thanks !!
Original Message:
Sent: 11-12-2019 13:24
From: mengzhe hu
Subject: ospf nssa do not export the default route

You are correct. You don't need export policy to get 0/0 advertised on totally nssa. Your configuration looks correct though

 

Here I want to point out something:

1. On ROUTER A, You don't need to care about 0/0. No matter it has 0/0 or not in its RIB, it's going to generate 0/0 in LSDB

2. Check on ROUTER B, "show ospf database" and see if you can see 0/0 entry if you don't have export policy on router A