topic Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR in Routing and SD-WAN

injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sat, 08 Sep 2018 14:59:18 GMT

What I want to do here is to generate a default-route on BR4 ( Totally NSSA ) which till this part it is simple

BR4(config-router)#area 4 nssa default-information-originate metric-type 1

and advertisement of this default-route reaches the HQ ( ABR & ASBR ) but the HQ does not consider it,

how can I make the HQ to consider it , what are the ways to do that ?

I appreciate any help that I can get.

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sat, 08 Sep 2018 18:04:27 GMT

Hello,

I don't see how HQ and BR4 are forming an adjacency. The link between both appears to be 44.44.44.0/29, but the interfaces on which these addresses are configured are not part of any area.

Please clarify how you make HQ and BR4 be part of area 4.

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sat, 08 Sep 2018 18:45:17 GMT

Georg Pauwen

Thanks for replying

they are connected through Tunnel4

BR4#show ip ospf int bri
Interface    PID   Area            IP Address/Mask    Cost State Nbrs F/C
Tu4          1     4               10.4.4.4/24        1000 P2P   1/1

BR4#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.0.4.0           0   FULL/ -        00:00:32    10.4.4.1        Tunnel4
BR4#show ip int bri
Interface                  IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0         192.168.122.67 YES DHCP   up                    up
GigabitEthernet0/1         44.44.44.2      YES NVRAM up                    up
GigabitEthernet0/2         192.168.40.1    YES manual up                    up
GigabitEthernet0/3         unassigned      YES NVRAM administratively down down
Loopback4                  9.9.9.9         YES NVRAM up                    up
NVI0                       192.168.122.67 YES unset up                    up
Tunnel4                    10.4.4.4        YES NVRAM up                    up
BR4#

HQ#show ip ospf interface brief
Interface    PID   Area            IP Address/Mask    Cost State Nbrs F/C
Gi0/2     1     0               172.16.2.1/29    1       BDR   1/1
Gi0/1       1     0               172.16.1.1/29        1       BDR   1/1
Tu123        1     1               192.168.123.1/28   1000    DR     2/2
Tu4            1     4               10.4.4.1/24       1000    P2P   1/1
HQ#
HQ#

HQ#show ip ospf neighbor

Neighbor ID     Pri   State         Dead Time   Address          Interface
5.0.4.0           1   FULL/DR       00:00:38    172.16.2.2    GigabitEthernet0/2
4.0.4.0           1   FULL/DR           00:00:37    172.16.1.2    GigabitEthernet0/1
2.0.4.0           0   FULL/DROTHER 00:00:39    192.168.123.2   Tunnel123
3.0.4.0           0   FULL/DROTHER 00:00:31    192.168.123.3   Tunnel123
44.0.4.0          0   FULL/ -      00:00:37    10.4.4.4         Tunnel4
HQ#
HQ#
HQ#show ip int
HQ#show ip interface br
HQ#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0         1.1.1.2         YES NVRAM up                    up
GigabitEthernet0/1         172.16.1.1      YES NVRAM up                    up
GigabitEthernet0/2         172.16.2.1      YES NVRAM up                    up
GigabitEthernet0/3         44.44.44.1      YES NVRAM up                    up
GigabitEthernet0/4         192.168.122.160 YES DHCP   up                    up
Loopback1                  11.11.11.11     YES NVRAM up                    up
Loopback4                  8.8.8.8         YES NVRAM up                    up
NVI0                       11.11.11.11     YES unset up                    up
Tunnel4                    10.4.4.1        YES NVRAM up                    up
Tunnel123                  192.168.123.1   YES NVRAM up                    up
HQ#

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sat, 08 Sep 2018 19:19:45 GMT

Hello,

your default route, most likely, appears as an N1 route in the routing table of HQ:

O*N1 0.0.0.0/0 [110/1001] via 10.4.4.4, 00:00:09, Tunnel4

That means intra/inter/E1 routes will be considered first. What do you want to achieve ?

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sat, 08 Sep 2018 20:19:18 GMT

Hello,

yes that is what I want to see in HQ routing table since I even get the advertisement of that type-7 default-route from BR4 but still I can't see a default-route ( O N1 ) int HQ routing table ,

HQ#show ip int bri
Interface                  IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0         1.1.1.2         YES NVRAM up                    up
GigabitEthernet0/1         172.16.1.1      YES NVRAM up                    up
GigabitEthernet0/2         172.16.2.1      YES NVRAM up                    up
GigabitEthernet0/3         44.44.44.1      YES NVRAM up                    up
GigabitEthernet0/4         192.168.122.160 YES DHCP   up                    up
Loopback1                  11.11.11.11     YES NVRAM up                    up
Loopback4                  8.8.8.8         YES NVRAM up                    up
NVI0                       11.11.11.11     YES unset up                    up
Tunnel4                    10.4.4.1        YES NVRAM up                    up
Tunnel123                  192.168.123.1   YES NVRAM up                    up

HQ#show ip route

Gateway of last resort is 192.168.122.1 to network 0.0.0.0

S*    0.0.0.0/0 [254/0] via 192.168.122.1
      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/30 is directly connected, GigabitEthernet0/0
L        1.1.1.2/32 is directly connected, GigabitEthernet0/0
      2.0.0.0/30 is subnetted, 1 subnets
S        2.2.2.0 [1/0] via 1.1.1.1
      3.0.0.0/30 is subnetted, 1 subnets
S        3.3.3.0 [1/0] via 1.1.1.1
      4.0.0.0/30 is subnetted, 1 subnets
S        4.4.4.0 [1/0] via 1.1.1.1
      8.0.0.0/32 is subnetted, 1 subnets
C        8.8.8.8 is directly connected, Loopback4
      9.0.0.0/32 is subnetted, 1 subnets
S        9.9.9.9 [1/0] via 44.44.44.2
      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.4.4.0/24 is directly connected, Tunnel4
L        10.4.4.1/32 is directly connected, Tunnel4
      11.0.0.0/32 is subnetted, 1 subnets
C        11.11.11.11 is directly connected, Loopback1
      44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        44.44.44.0/29 is directly connected, GigabitEthernet0/3
L        44.44.44.1/32 is directly connected, GigabitEthernet0/3
      172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks
C        172.16.1.0/29 is directly connected, GigabitEthernet0/1
L        172.16.1.1/32 is directly connected, GigabitEthernet0/1
C        172.16.2.0/29 is directly connected, GigabitEthernet0/2
L        172.16.2.1/32 is directly connected, GigabitEthernet0/2
O        172.16.12.0/24 [110/2] via 172.16.2.2, 00:00:45, GigabitEthernet0/2
                        [110/2] via 172.16.1.2, 00:00:52, GigabitEthernet0/1
      192.168.122.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.122.0/24 is directly connected, GigabitEthernet0/4
L        192.168.122.160/32 is directly connected, GigabitEthernet0/4
      192.168.123.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.123.0/28 is directly connected, Tunnel123
L        192.168.123.1/32 is directly connected, Tunnel123
HQ#

HQ#conf t
Enter configuration commands, one per line. End with CNTL/Z.
HQ(config)#int g0/4
HQ(config-if)#shu
HQ(config-if)#shutdown

HQ(config-if)#
*Sep 8 20:09:05.108: %LINK-5-CHANGED: Interface GigabitEthernet0/4, changed state to administratively down
*Sep 8 20:09:06.107: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/4, changed state to down
HQ(config-if)#do show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/30 is directly connected, GigabitEthernet0/0
L        1.1.1.2/32 is directly connected, GigabitEthernet0/0
      2.0.0.0/30 is subnetted, 1 subnets
S        2.2.2.0 [1/0] via 1.1.1.1
      3.0.0.0/30 is subnetted, 1 subnets
S        3.3.3.0 [1/0] via 1.1.1.1
      4.0.0.0/30 is subnetted, 1 subnets
S        4.4.4.0 [1/0] via 1.1.1.1
      8.0.0.0/32 is subnetted, 1 subnets
C        8.8.8.8 is directly connected, Loopback4
      9.0.0.0/32 is subnetted, 1 subnets
S        9.9.9.9 [1/0] via 44.44.44.2
      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.4.4.0/24 is directly connected, Tunnel4
L        10.4.4.1/32 is directly connected, Tunnel4
      11.0.0.0/32 is subnetted, 1 subnets
C        11.11.11.11 is directly connected, Loopback1
      44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        44.44.44.0/29 is directly connected, GigabitEthernet0/3
L        44.44.44.1/32 is directly connected, GigabitEthernet0/3
      172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks
C        172.16.1.0/29 is directly connected, GigabitEthernet0/1
L        172.16.1.1/32 is directly connected, GigabitEthernet0/1
C        172.16.2.0/29 is directly connected, GigabitEthernet0/2
L        172.16.2.1/32 is directly connected, GigabitEthernet0/2
O        172.16.12.0/24 [110/2] via 172.16.2.2, 00:02:10, GigabitEthernet0/2
                        [110/2] via 172.16.1.2, 00:02:17, GigabitEthernet0/1
      192.168.123.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.123.0/28 is directly connected, Tunnel123
L        192.168.123.1/32 is directly connected, Tunnel123
HQ(config-if)#

HQ#show ip ospf database

            OSPF Router with ID (1.0.4.0) (Process ID 1)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         435         0x80000005 0x0040D2 2
4.0.4.0         4.0.4.0         441         0x80000004 0x0012B4 2
5.0.4.0         5.0.4.0         440         0x80000004 0x002A98 2

                Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
172.16.1.2      4.0.4.0         441         0x80000001 0x00105C
172.16.2.2      5.0.4.0         436         0x80000003 0x00FE68

                Summary Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
10.4.4.0        1.0.4.0         431         0x80000001 0x00B980
192.168.123.0   1.0.4.0         431         0x80000001 0x003E38

                Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         437         0x80000002 0x00342F 1

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
10.4.4.0        1.0.4.0         431         0x80000001 0x00B980
172.16.1.0      1.0.4.0         439         0x80000001 0x00B3CC
172.16.2.0      1.0.4.0         439         0x80000001 0x00A8D6
172.16.12.0     1.0.4.0         439         0x80000001 0x006EFE

                Router Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         432         0x80000005 0x00568A 2
44.0.4.0        44.0.4.0        438         0x80000005 0x00991A 2

                Summary Net Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         1.0.4.0         439         0x80000001 0x00141D

                Type-7 AS External Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum Tag
0.0.0.0         44.0.4.0        1165        0x80000001 0x007271 0
8.8.8.8         44.0.4.0        1166        0x80000002 0x0089A1 4

so I believe that I should have that O*N1 default-route in HQ routing table , so the question is why I don't?

and to achieve that what are the ways ?

Thanks.

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sat, 08 Sep 2018 20:43:44 GMT

Hello,

change the static route on BR4 from:

ip route 0.0.0.0 0.0.0.0 192.168.122.1 22

ip route 0.0.0.0 0.0.0.0 null 0

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sat, 08 Sep 2018 23:07:36 GMT

Hi,

I did it but no result,

I add another Router (ISP1) to the BR4 which receives the default-route by BGP and again it is the same and HQ does receive the type-7 default-route but it does not add it to its routing table.

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sun, 09 Sep 2018 08:01:12 GMT

Hello,

remove the 'redistribute static' from your OSPF on BR4:

router ospf 1
router-id 44.0.4.0
area 4 nssa default-information-originate metric-type 1
--> no redistribute static subnets tag 4
network 10.4.4.4 0.0.0.0 area 4

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sun, 09 Sep 2018 10:41:22 GMT

Heloo,

Thanks for the help.

I did that but it didn't work either.

but I could achieve it by going to the HQ and issuing #no area 4 nssa no-summary and # area 4 nssa

as follows :

HQ(config-router)#do show ip ospf data sum

            OSPF Router with ID (1.0.4.0) (Process ID 1)

                Summary Net Link States (Area 0)

LS age: 82
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 5.0.0.4 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x271E
Length: 28
Network Mask: /30
        MTID: 0         Metric: 1001

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 10.4.4.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xB980
Length: 28
Network Mask: /24
        MTID: 0         Metric: 1000

LS age: 600
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.1.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xE877
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001

LS age: 600
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.1.128 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xE3FB
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001

LS age: 610
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.2.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xDD81
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001

LS age: 610
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.2.128 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xD806
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001

LS age: 82
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.40.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x3AFE
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.123.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x3E38
Length: 28
Network Mask: /28
        MTID: 0         Metric: 1000


                Summary Net Link States (Area 1)

LS age: 82
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 5.0.0.4 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x271E
Length: 28
Network Mask: /30
        MTID: 0         Metric: 1001

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 10.4.4.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xB980
Length: 28
Network Mask: /24
        MTID: 0         Metric: 1000

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 172.16.1.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xB3CC
Length: 28
Network Mask: /29
        MTID: 0         Metric: 1

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 172.16.2.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xA8D6
Length: 28
Network Mask: /29
        MTID: 0         Metric: 1

LS age: 645
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 172.16.12.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x6EFE
Length: 28
Network Mask: /24
        MTID: 0         Metric: 2

LS age: 82
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 192.168.40.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0x3AFE
Length: 28
Network Mask: /25
        MTID: 0         Metric: 1001


                Summary Net Link States (Area 4)

LS age: 93
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(Network)
Link State ID: 0.0.0.0 (summary Network Number)
Advertising Router: 1.0.4.0
LS Seq Number: 80000001
Checksum: 0xC342
Length: 28
Network Mask: /0
        MTID: 0         Metric: 44

HQ(config-router)#do show ip ospf data

            OSPF Router with ID (1.0.4.0) (Process ID 1)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         667         0x80000008 0x003A9C 2
5.0.4.0         5.0.4.0         1559        0x80000005 0x002899 2

                Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
172.16.2.2      5.0.4.0         1559        0x80000003 0x00FE68

                Summary Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
5.0.0.4         1.0.4.0         94          0x80000001 0x00271E
10.4.4.0        1.0.4.0         657         0x80000001 0x00B980
192.168.1.0     1.0.4.0         611         0x80000001 0x00E877
192.168.1.128   1.0.4.0         611         0x80000001 0x00E3FB
192.168.2.0     1.0.4.0         621         0x80000001 0x00DD81
192.168.2.128   1.0.4.0         621         0x80000001 0x00D806
192.168.40.0    1.0.4.0         94          0x80000001 0x003AFE
192.168.123.0   1.0.4.0         657         0x80000001 0x003E38

                Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         626         0x8000000B 0x0073F1 1
2.0.4.0         2.0.4.0         626         0x8000000C 0x00F4F6 3
3.0.4.0         3.0.4.0         627         0x8000000B 0x0025C2 3

                Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
192.168.123.1   1.0.4.0         621         0x80000002 0x000344

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
5.0.0.4         1.0.4.0         94          0x80000001 0x00271E
10.4.4.0        1.0.4.0         657         0x80000001 0x00B980
172.16.1.0      1.0.4.0         657         0x80000001 0x00B3CC
172.16.2.0      1.0.4.0         657         0x80000001 0x00A8D6
172.16.12.0     1.0.4.0         657         0x80000001 0x006EFE
192.168.40.0    1.0.4.0         94          0x80000001 0x003AFE

                Router Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.0.4.0         1.0.4.0         98          0x8000000A 0x004C8F 2
44.0.4.0        44.0.4.0        99          0x80000009 0x007EF2 4

                Summary Net Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         1.0.4.0         105         0x80000001 0x00C342

                Type-7 AS External Link States (Area 4)

Link ID         ADV Router      Age         Seq#       Checksum Tag
0.0.0.0         44.0.4.0        249         0x80000001 0x00E40B 0
8.8.4.0         44.0.4.0        241         0x80000004 0x006DEA 0

                Type-5 AS External Link States

Link ID         ADV Router      Age         Seq#       Checksum Tag
8.8.4.0         1.0.4.0         93          0x80000001 0x008C04 0
HQ(config-router)#do show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/30 is directly connected, GigabitEthernet0/0
L        1.1.1.2/32 is directly connected, GigabitEthernet0/0
      2.0.0.0/30 is subnetted, 1 subnets
S        2.2.2.0 [1/0] via 1.1.1.1
      3.0.0.0/30 is subnetted, 1 subnets
S        3.3.3.0 [1/0] via 1.1.1.1
      4.0.0.0/30 is subnetted, 1 subnets
S        4.4.4.0 [1/0] via 1.1.1.1
      5.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O        5.0.0.4/30 is a summary, 00:01:46, Null0
O        5.0.0.5/32 [110/1001] via 10.4.4.4, 00:01:46, Tunnel4
      8.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O N2     8.8.4.0/24 [110/1] via 10.4.4.4, 00:01:46, Tunnel4
C        8.8.8.8/32 is directly connected, Loopback4
      9.0.0.0/32 is subnetted, 1 subnets
S        9.9.9.9 [1/0] via 44.44.44.2
      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.4.4.0/24 is directly connected, Tunnel4
L        10.4.4.1/32 is directly connected, Tunnel4
      11.0.0.0/32 is subnetted, 1 subnets
C        11.11.11.11 is directly connected, Loopback1
      44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        44.44.44.0/29 is directly connected, GigabitEthernet0/3
L        44.44.44.1/32 is directly connected, GigabitEthernet0/3
      172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks
C        172.16.1.0/29 is directly connected, GigabitEthernet0/1
L        172.16.1.1/32 is directly connected, GigabitEthernet0/1
C        172.16.2.0/29 is directly connected, GigabitEthernet0/2
L        172.16.2.1/32 is directly connected, GigabitEthernet0/2
O        172.16.12.0/24 [110/2] via 172.16.2.2, 00:01:57, GigabitEthernet0/2
      192.168.1.0/25 is subnetted, 2 subnets
O        192.168.1.0 [110/1001] via 192.168.123.2, 00:01:57, Tunnel123
O        192.168.1.128 [110/1001] via 192.168.123.2, 00:01:57, Tunnel123
      192.168.2.0/25 is subnetted, 2 subnets
O        192.168.2.0 [110/1001] via 192.168.123.3, 00:01:57, Tunnel123
O        192.168.2.128 [110/1001] via 192.168.123.3, 00:01:57, Tunnel123
      192.168.40.0/25 is subnetted, 1 subnets
O        192.168.40.0 [110/1001] via 10.4.4.4, 00:01:46, Tunnel4
      192.168.123.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.123.0/28 is directly connected, Tunnel123
L        192.168.123.1/32 is directly connected, Tunnel123
HQ(config-router)#do show run | sec ospf
ip ospf 1 area 4
ip ospf network broadcast
redistribute ospf 1 metric 100 5000 255 2 17916
router ospf 1
router-id 1.0.4.0
area 4 nssa no-summary
area 4 default-cost 44
area 4 range 5.0.0.4 255.255.255.252
redistribute eigrp 100 metric-type 1 subnets tag 100
network 172.16.1.0 0.0.0.7 area 0
network 172.16.2.0 0.0.0.7 area 0
network 192.168.123.0 0.0.0.15 area 1
HQ(config-router)#no area 4 nssa no-summary
HQ(config-router)#do show run | sec ospf
ip ospf 1 area 4
ip ospf network broadcast
redistribute ospf 1 metric 100 5000 255 2 17916
router ospf 1
router-id 1.0.4.0
area 4 nssa
area 4 default-cost 44
area 4 range 5.0.0.4 255.255.255.252
redistribute eigrp 100 metric-type 1 subnets tag 100
network 172.16.1.0 0.0.0.7 area 0
network 172.16.2.0 0.0.0.7 area 0
network 192.168.123.0 0.0.0.15 area 1
HQ(config-router)#do show ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       a - application route
       + - replicated route, % - next hop override, p - overrides from PfR

Gateway of last resort is 10.4.4.4 to network 0.0.0.0

O*N1 0.0.0.0/0 [110/1002] via 10.4.4.4, 00:00:18, Tunnel4
      1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        1.1.1.0/30 is directly connected, GigabitEthernet0/0
L        1.1.1.2/32 is directly connected, GigabitEthernet0/0
      2.0.0.0/30 is subnetted, 1 subnets
S        2.2.2.0 [1/0] via 1.1.1.1
      3.0.0.0/30 is subnetted, 1 subnets
S        3.3.3.0 [1/0] via 1.1.1.1
      4.0.0.0/30 is subnetted, 1 subnets
S        4.4.4.0 [1/0] via 1.1.1.1
      5.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O        5.0.0.4/30 is a summary, 00:00:18, Null0
O        5.0.0.5/32 [110/1001] via 10.4.4.4, 00:00:18, Tunnel4

      8.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O N2     8.8.4.0/24 [110/1] via 10.4.4.4, 00:00:18, Tunnel4
C        8.8.8.8/32 is directly connected, Loopback4
      9.0.0.0/32 is subnetted, 1 subnets
S        9.9.9.9 [1/0] via 44.44.44.2
      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.4.4.0/24 is directly connected, Tunnel4
L        10.4.4.1/32 is directly connected, Tunnel4
      11.0.0.0/32 is subnetted, 1 subnets
C        11.11.11.11 is directly connected, Loopback1
      44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        44.44.44.0/29 is directly connected, GigabitEthernet0/3
L        44.44.44.1/32 is directly connected, GigabitEthernet0/3
      172.16.0.0/16 is variably subnetted, 5 subnets, 3 masks
C        172.16.1.0/29 is directly connected, GigabitEthernet0/1
L        172.16.1.1/32 is directly connected, GigabitEthernet0/1
C        172.16.2.0/29 is directly connected, GigabitEthernet0/2
L        172.16.2.1/32 is directly connected, GigabitEthernet0/2
O        172.16.12.0/24 [110/2] via 172.16.2.2, 00:00:18, GigabitEthernet0/2
      192.168.1.0/25 is subnetted, 2 subnets
O        192.168.1.0 [110/1001] via 192.168.123.2, 00:00:18, Tunnel123
O        192.168.1.128 [110/1001] via 192.168.123.2, 00:00:18, Tunnel123
      192.168.2.0/25 is subnetted, 2 subnets
O        192.168.2.0 [110/1001] via 192.168.123.3, 00:00:18, Tunnel123
O        192.168.2.128 [110/1001] via 192.168.123.3, 00:00:18, Tunnel123
      192.168.40.0/25 is subnetted, 1 subnets
O        192.168.40.0 [110/1001] via 10.4.4.4, 00:00:18, Tunnel4
      192.168.123.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.123.0/28 is directly connected, Tunnel123
L        192.168.123.1/32 is directly connected, Tunnel123
HQ(config-router)#

So I think the reason is that since the HQ will automatically advertises a default-route into totally NSSA and because of that it doesn't consider the default-route info received from BR4 ( I also issued #area 4 default-cost 44 , which had no effect to prefer the BR4's default-route) , so when I configured the area 4 just as NSSA on HQ then it is able to accept and consider the BR4's default-route and put it in its routing table.

Now the question is that how can I do have that default-route in HQ's routing table if the area 4 be configured as totally NSSA ?

Thanks again.

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

paul driver — Mon, 10 Sep 2018 11:25:21 GMT

Hello

i am not able to view all the reply’s at present but just reading your OP if your peering ospf over tunnel is if that tunnel assigned to backbone area 0 ?

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sun, 09 Sep 2018 11:47:25 GMT

Hello,

no it is assigned to to area 4

HQ#show ip ospf int bri
Interface PID   Area            IP Address/Mask    Cost     State Nbrs F/C
Gi0/2         1    0               172.16.2.1/29            1        DR   0/0
Gi0/1       1    0               172.16.1.1/29        1        DR   0/0
Tu123        1     1               192.168.123.1/28    1000 DR   1/1
Tu4        1        4               10.4.4.1/24               1000 P2P   1/1

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

paul driver — Mon, 10 Sep 2018 11:28:05 GMT

Hello

If your trying to inject a default route into area 0 from a non backbone nssa - my understanding it will not be allowed

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sun, 09 Sep 2018 12:59:52 GMT

Hello,

it does not allow when HQ knows the area 4 as totally NSSA but it allows that when HQ knows the area 4 as NSSA and BR4 has an actual default-route through BGP and is redistributed to ospf .

But I wanted to do so i.e I want to have that default-route usable in HQ advertised by BR4 to HQ which I can see that HQ can receive the advertisement of that default-route but does not consider it , since HQ considers the other redistributed routes from BGP into ospf by BR4 .

so by your understanding :

HQ(ABR & ASBR) won't accept default-route advertised by BR4 ( area 4) and it is not possible if the area 4 is Totally NSSA ?!

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sun, 09 Sep 2018 15:51:29 GMT

Hello,

I recreated your setup in GNS3, with back to back routers, the default route is injected as expected on HQ:

interface Loopback4
ip address 8.8.8.8 255.255.255.255
!
interface Tunnel4
ip address 10.4.4.1 255.255.255.0
ip ospf 1 area 4
tunnel source Loopback4
tunnel destination 9.9.9.9
!
interface GigabitEthernet0/0
ip address 44.44.44.1 255.255.255.248
duplex auto
speed auto
media-type rj45
!
router ospf 1
router-id 8.8.8.8
area 4 nssa no-summary
!
ip route 9.9.9.9 255.255.255.255 44.44.44.2

BR4

interface Loopback4
ip address 9.9.9.9 255.255.255.255
!
interface Tunnel4
ip address 10.4.4.2 255.255.255.0
ip ospf 1 area 4
tunnel source Loopback4
tunnel destination 8.8.8.8
!
interface GigabitEthernet0/0
ip address 44.44.44.2 255.255.255.248
duplex auto
speed auto
media-type rj45
no cdp enable
!
router ospf 1
area 4 nssa default-information-originate no-summary
!
ip route 0.0.0.0 0.0.0.0 Null0
ip route 8.8.8.8 255.255.255.255 44.44.44.1

HQ#sh ip route

Gateway of last resort is 10.4.4.2 to network 0.0.0.0

O*N2 0.0.0.0/0 [110/1] via 10.4.4.2, 00:03:01, Tunnel4
8.0.0.0/32 is subnetted, 1 subnets
C 8.8.8.8 is directly connected, Loopback4
9.0.0.0/32 is subnetted, 1 subnets
S 9.9.9.9 [1/0] via 44.44.44.2
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.4.4.0/24 is directly connected, Tunnel4
L 10.4.4.1/32 is directly connected, Tunnel4
44.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 44.44.44.0/29 is directly connected, GigabitEthernet0/0
L 44.44.44.1/32 is directly connected, GigabitEthernet0/0

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Sun, 09 Sep 2018 21:51:00 GMT

Hello,

Thanks.

I did a separate GNS3 with just 3 routers ( (VIOS-ADVENTERPRISEK9-M), Version 15.6(2)T ) just for area 0 and 4 but the result is still the same .

I don't get it !

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sun, 09 Sep 2018 21:53:58 GMT

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Georg Pauwen — Sun, 09 Sep 2018 21:55:48 GMT

Weird indeed. Can you attach the GNS3 file ? I am using the same IOS, so I should be able to open it...

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

paul driver — Mon, 10 Sep 2018 12:18:39 GMT

Hello

@Mehdi.a.majid1 wrote:

Hello,

it does not allow when HQ knows the area 4 as totally NSSA but it allows that when HQ knows the area 4 as NSSA and BR4 has an actual default-route through BGP and is redistributed to ospf .

But I wanted to do so i.e I want to have that default-route usable in HQ advertised by BR4 to HQ which I can see that HQ can receive the advertisement of that default-route but does not consider it , since HQ considers the other redistributed routes from BGP into ospf by BR4 .

so by your understanding :

HQ(ABR & ASBR) won't accept default-route advertised by BR4 ( area 4) and it is not possible if the area 4 is Totally NSSA ?!

Okay, have your tried using the "no-redistribution" to negate redistribution of the bgp prefixes but retain the default

BR4

area 3 nssa no-redistribution default-information-originate no-summary

HQ
area 3 nssa

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

paul driver — Mon, 10 Sep 2018 12:44:08 GMT

Hello

Additionally looking at your topology you could suppress type 7 forwarding address translation so area routers off the backbone will have a forwarding address of the HQ ABR and not the ASBR

HQ
area 3 nssa translate type7 suppress-fa

Re: injecting a default-route by an ASBR into OSPF domain and reaching the ABR

Mehdi.a.majid1 — Mon, 10 Sep 2018 14:21:05 GMT

Hello,

I attached the zip file

Thanks.