OSPF NSSA - getting a default route

From: Ekis, Joel (Joel.Ekis@xxxxxxxxxxxxxxxxx)
Date: Tue Jun 15 1999 - 15:20:39 GMT-3


   
I have been testing various configuration of a stub area. Here's the
network:

<RIP> --- 25T --- <OSPF area 5> --- 4kT --- <OSPF area 0> --- 4kE ---
<EIGRP>

When I configure the 25T and 4kT routers with no 'stub' commands, then all
the routes (C, O IA, O E2, and O*E2) all are present in the 25T router. The
4kT router has all its routes (C, O, O E2, O*E2). Every interface can ping
every other interface.

When I configure the 25T and 4kT with the 'area 5 stub', the 25T table
correctly has fewer routes (C, O IA, O*IA). Every interface can ping every
other interface. The RIP routes are not available in the 4kT router any
more (which is fine).

When I configure the 25T with 'area 5 stub' and the 4kT with 'area 5 stub
no-summary' this reduces the routing table in the 25T to only (C and O*IA).
All pings still work, except the RIP routes (which is fine).

When I configure the 25T and 4kT routers as Not-So-Stubby areas with 'area 5
nssa', I get all the routes in the 4kT I expect (C, O, O E2, O N2,O*E2).
However, the 25T has one fewer route than I expected. It has (C and O IA).
I lost the O*IA route that was my default to 0/0. Why? How do I get it
back.

Also, now the 25T router is trying to create a neighbor relation with the
4kE router! Which is in the DOWN/DROTHER state. Why? The 4kE is not
trying to make a relationship with the 25T router.

Here are some of the configs:

hostname 25T
interface Loopback0
 ip address 10.5.4.4 255.255.255.248
interface Loopback1
 ip address 172.19.1.1 255.255.255.0
interface TokenRing0
 ip address 10.10.2.17 255.255.248.0
 ring-speed 16
router ospf 1
 redistribute rip metric 3 subnets
 network 10.10.0.0 0.0.7.255 area 5
 network 10.5.4.0 0.0.0.7 area 5
 area 5 nssa
router rip
 network 172.19.0.0
ip classless

hostname 4kT
interface Serial0
 ip address 10.1.1.2 255.255.255.252
 bandwidth 256
interface TokenRing0
 ip address 10.10.3.3 255.255.248.0
 ring-speed 16
router ospf 1
 network 10.1.1.0 0.0.0.255 area 0
 network 10.10.0.0 0.0.7.255 area 5
 area 5 nssa
ip classless

hostname 4kE
interface Ethernet0
 ip address 172.16.1.1 255.255.255.128
interface Serial0
 ip address 10.1.1.1 255.255.255.252
 bandwidth 256
 clockrate 250000
router eigrp 300
 redistribute ospf 1 metric 10000 10 255 1 1500
 network 172.16.0.0
router ospf 1
 redistribute eigrp 300 metric 1000 subnets
 network 10.1.1.0 0.0.0.255 area 0
 default-information originate always
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.1.2

hostname 25E
interface Loopback0
 ip address 172.16.2.2 255.255.255.0
interface Loopback1
 ip address 172.16.3.2 255.255.255.224
interface Loopback2
 ip address 192.168.34.5 255.255.255.0
interface Ethernet0
 ip address 172.16.1.2 255.255.255.128
router eigrp 300
 network 172.16.0.0
ip classless

The 25E lo2 interface is not in any routing protocol. That is my test of
the default route.

Joel Ekis, CCNA, CCDA
Xerox Connect
Sr. Enterprise Consultant/Enterprise Network Services
Phone: 913-696-0888, x234
Pager: 800-697-0359
joel.ekis@connect.xerox.com <mailto:joel.ekis@connect.xerox.com>



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