Guerra de OSPF entre dos routers
Fecha: 8 y 11 de
septiembre del 2023
Escenario
Este laboratorio surge a partir de un caso real,
desde un router que debe ponerse en producción en un sitio
remoto, entonces previamente y a modo de test se
conecta localmente con resultados imprevistos, tal como
una “guerra de OSPF” entre los routers afectados,
el que tendrá conectado definitivamente el router remoto,
y el router anfitrión de las pruebas.
Una vez develado el enigma no hubo otra
alternativa que revalidarlo en una maqueta de testing.
Y allá vamos…
Captura de pantalla de los
dias previos y mientras se realizaba el t-shoot:
1.- Verificación inicial:
1.1.- En Router-A:
1.1.1.- Adyancencias OSPF:
Router-A#sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.2.1
0 FULL/DROTHER 00:00:36
10.0.0.2 Vlan10 (Router-B)
Router-A#
1.1.2.- En la tabla de
enrutamiento:
Router-A#sh 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
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C
10.0.0.0/30 is directly connected, Vlan10
L
10.0.0.1/32 is directly connected, Vlan10
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, Vlan1
L
192.168.1.1/32 is directly connected, Vlan1
O 192.168.2.0/24 [110/2] via 10.0.0.2,
00:01:39, Vlan10 (via
Router-B)
Router-A#
1.2.- En Router-B:
1.2.1.- Adyancencias OSPF:
Router-B# sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.1.1
255 FULL/DR 00:00:38 10.0.0.1 Vlan10 (Router-A)
Router-B#
1.2.2.- En la tabla de
enrutamiento:
Router-B#sh 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, + - replicated route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C
10.0.0.0/30 is directly connected, Vlan10
L
10.0.0.2/32 is directly connected, Vlan10
O 192.168.1.0/24 [110/2] via 10.0.0.1,
00:00:43, Vlan10 (via
Router-B)
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.2.0/24 is directly connected, Vlan2
L
192.168.2.1/32 is directly connected, Vlan2
Router-B#
2.- Se conecta Router-C
localmente y a modo maqueta para realizar pruebas/ajustes:
2.1.- Configuramos “la pata”
al Router-C:
Router-A#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router-A(config)#int vlan 14
Router-A(config-if)#ip add 10.0.0.5
255.255.255.252
Router-A(config-if)#ip ospf priority 255 (para asegurarse ser el DR)
Router-A(config-if)#exit
Router-A(config)#
Router-A(config)#int fa1
Router-A(config-if)#sw mode access
Router-A(config-if)#sw access vlan 14
Router-A(config-if)#exit
Router-A(config)#
Router-A(config)#router ospf 1
Router-A(config-router)#network 10.0.0.4 0.0.0.3 area 0
Router-A(config-router)#end
Router-A#
Sep 8 13:39:52.608: %OSPF-5-ADJCHG: Process 1,
Nbr 192.168.3.1 on Vlan14 from LOADING to FULL, Loading Done
Router-A#
Router-C#
Sep 8 13:39:19: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.1.1
on FastEthernet0/1 from LOADING to FULL, Loading Done
Router-C#
2.2.- Verificamos
adyacencias OSPF en el Router-A:
Router-A# sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address
Interface
192.168.3.1 0
FULL/DROTHER 00:00:39
10.0.0.6 Vlan14 (Router-C)
192.168.2.1 0
FULL/DROTHER 00:00:39
10.0.0.2 Vlan10 (Router-B)
Router-A#
2.3.- Verificamos
adyacencias OSPF en el Router-C:
Router-C#sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.1.1 255
FULL/DR
00:00:37 10.0.0.5 FastEthernet0/1 (Router-A)
Router-C#
2.4.- Verificamos en la
tabla de enrutamiento del Router-A:
Router-A#sh 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
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C
10.0.0.0/30 is directly connected, Vlan10
L
10.0.0.1/32 is directly connected, Vlan10
C
10.0.0.4/30 is directly connected, Vlan14
L
10.0.0.5/32 is directly connected, Vlan14
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected,
Vlan1
L
192.168.1.1/32 is directly connected, Vlan1
O 192.168.2.0/24 [110/2] via 10.0.0.2,
00:19:10, Vlan10 (via Router-B)
O 192.168.3.0/24 [110/2] via 10.0.0.6,
00:03:41, Vlan14 (via Router-C)
Router-A#
2.5.- Verificamos en la
tabla de enrutamiento del Router-C:
Router-C#sh ip route
Codes: 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
Gateway of last resort is not set
10.0.0.0/30 is subnetted, 2 subnets
O
10.0.0.0 [110/2] via 10.0.0.5, 00:03:01, FastEthernet0/1 (segmento Router-A – RouterB)
C 10.0.0.4
is directly connected, FastEthernet0/1
O
192.168.1.0/24 [110/2] via 10.0.0.5, 00:03:01, FastEthernet0/1 (via Router-B / Router-A)
O
192.168.2.0/24 [110/3] via 10.0.0.5, 00:03:01, FastEthernet0/1 (via Router-A)
C
192.168.3.0/24 is directly connected, FastEthernet0/0
Router-C#
2.6.- Verificamos que
Router-B no aprende la red 192.168.3.0:
Router-B#sh 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, + - replicated route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C
10.0.0.0/30 is directly connected, Vlan10
L
10.0.0.2/32 is directly connected, Vlan10
O 192.168.1.0/24 [110/2] via 10.0.0.1,
00:01:39, Vlan10 (via
Router-A)
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.2.0/24 is directly connected,
Vlan2
L
192.168.2.1/32 is directly connected, Vlan2
Router-B#
2.7.- Comienzan los logs:
Router-A#
Sep 8 13:43:41.761: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:45:46.500: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:47:51.655: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:49:56.726: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:52:01.460: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:54:06.763: %OSPF-4-FLOOD_WAR: Process 1
re-originates LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Router-A#
Router-B#
Sep 8 13:43:41.399: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:45:50.439: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:47:55.455: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:49:00.475: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:52:05.495: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Sep 8 13:54:15.659: %OSPF-4-FLOOD_WAR: Process 1
flushes LSA ID 10.0.0.5 type-2 adv-rtr 192.168.1.1 in area 0
Router-B#
3.- Verificamos con una
captura de Wireshark:
Frame 1: 94 bytes on
wire (752 bits), 94 bytes captured (752 bits) on id 0
Ethernet II, Src: cc:46:d6:2b:5a:54, Dst:
01:00:5e:00:00:05
Internet Protocol Version 4, Src: 10.0.0.1, Dst:
224.0.0.5
Open Shortest Path First
OSPF
Header
LS
Update Packet
Number of LSAs: 1
LSA-type 2 (Network-LSA), len 32
.000 0000 0000 0001 = LS Age (seconds): 1
0... .... .... .... = Do Not Age Flag: 0
Options: 0x22, (DC) Demand Circuits, (E) External Routing
LS Type: Network-LSA (2)
Link State ID: 10.0.0.5
Advertising Router: 192.168.1.1
Sequence Number: 0x80000057
Checksum: 0x167d
Length: 32
Netmask: 255.255.255.252
Attached Router: 192.168.1.1
Attached Router: 192.168.3.1
Frame 2: 94 bytes on
wire (752 bits), 94 bytes captured (752 bits) on interface id 0
Ethernet II, Src: 70:81:05:b5:77:82, Dst:
01:00:5e:00:00:06
Internet Protocol Version 4, Src: 10.0.0.2, Dst:
224.0.0.6
Open Shortest Path First
OSPF
Header
LS
Update Packet
Number of LSAs: 1
LSA-type
2 (Network-LSA), len 32
.000 1110 0001 0000 = LS Age (seconds): 3600 (si MaxAge es igual a 1 hora (3600
segundos) se purga de los cálculos OSPF)
0... .... .... .... = Do Not Age Flag: 0
Options: 0x22, (DC) Demand Circuits, (E) External Routing
LS Type: Network-LSA (2)
Link State ID: 10.0.0.5 (la IP duplicada en ambos routers
que causa el war flooding)
Advertising Router: 192.168.1.1
Sequence Number: 0x80000057
Checksum: 0x167d
Length: 32
Netmask: 255.255.255.252 (la máscara del segmento en disputa)
Attached Router: 192.168.1.1
Attached Router: 192.168.3.1
4.- Verificamos con debug:
4.1.- En Router-A:
Router-A#debug ip ospf flood
OSPF flooding debugging is on
Router-A#
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Add Type
2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to 192.168.3.1
retransmission list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Add Type
2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to flood list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Flooding
update to 224.0.0.5 Area 0
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Send Type 2, LSID 10.0.0.5, Adv rtr 192.168.1.1, age 1, seq 0x80000057 (0)
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Remove
Type 2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 flood list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl14: Stop
flood timer
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Add Type
2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to 192.168.2.1
retransmission list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Add Type
2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to flood list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Flooding
update to 224.0.0.5 Area 0
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Send Type
2, LSID 10.0.0.5, Adv rtr 192.168.1.1, age 1, seq 0x80000057 (0)
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Remove
Type 2 LSA ID 10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 flood list
Sep 11 15:38:12.079: OSPF-1 FLOOD Vl10: Stop
flood timer
Sep 11 15:38:11.751: OSPF-1 FLOOD Vl10: Received
update from 192.168.2.1 (Router-B)
Sep 11 15:38:11.751: OSPF-1 FLOOD Vl10: Rcv Update Type 2, LSID 10.0.0.5, Adv rtr 192.168.1.1, age 3600, seq 0x80000057 Mask /30
Sep 11 15:38:11.751: OSPF-1 FLOOD Vl10: we
received our own old net lsa
|
Router-A#
(si MaxAge es igual a
1 hora (3600 segundos) se purga de los cálculos OSPF)
4.2.- En Router-B:
Router-B#debug ip ospf flood
OSPF flooding debugging is on
Router-B#
Sep 11 15:38:11.231: OSPF: received update from
192.168.1.1, Vlan10 (Router-A)
Sep 11 15:38:11.231: OSPF: Rcv Update Type 2, LSID 10.0.0.5, Adv rtr 192.168.1.1, age 1, seq 0x80000057
Sep 11 15:38:11.231: Mask /30
Sep 11 15:38:11.235: OSPF: Remove Type 2 LSA ID
10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 from 192.168.1.1 retransmission list
Sep 11 15:38:11.235: OSPF: Add Type 2 LSA ID
10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to Vlan10 192.168.1.1 retransmission
list
Sep 11 15:38:11.235: OSPF: Add Type 2 LSA ID
10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 to Vlan10 flood list
Sep 11 15:38:11.235: OSPF: Sending update over
Vlan10 without pacing
Sep 11 15:38:11.235: OSPF: Flooding update on
Vlan10 to 224.0.0.6 Area 0
Sep 11 15:38:11.235: OSPF: Send Type 2, LSID 10.0.0.5, Adv rtr 192.168.1.1, age 3600, seq 0x80000057 (0)
Sep 11 15:38:11.235: OSPF: Remove Type 2 LSA ID
10.0.0.5 Adv rtr 192.168.1.1 Seq 80000057 from Vlan10 flood list
Sep 11 15:38:11.235: OSPF: Stop Vlan10 flood
timer
Sep 11 15:38:13.735: OSPF: Sending delayed ACK on
Vlan10
Sep 11 15:38:13.735: OSPF: Ack Type 2, LSID
10.0.0.5, Adv rtr 192.168.1.1, age 1, seq 0x80000057
Router-B#
5.- Verificamos las IP de
los routers:
5.1.- en Router-A:
Router-A#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0 unassigned YES unset up up (el
segmento Router-A – Router-B)
FastEthernet1 unassigned YES unset up up (el
segmento Router-A – Router-C)
FastEthernet2 unassigned YES unset up up (el
segmento LAN 192.168.1.0/24)
FastEthernet3 unassigned YES unset down up
Vlan1 192.168.1.1 YES manual
up up
Vlan10 10.0.0.1 YES manual up up
Vlan14 10.0.0.5 YES manual up up (el segmento de test Router-A - Router-C)
Router-A#
5.2.- en Router-B:
Router-B#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0 unassigned YES unset up up (el segmento Router-B – Router-A)
FastEthernet1 unassigned YES unset down down (el segmento Router-B – Router-C)
FastEthernet2 unassigned YES unset up up (el segmento LAN 192.168.2.0/24)
FastEthernet3 unassigned YES unset down down
Vlan1 unassigned YES NVRAM up up
Vlan2 192.168.2.1 YES manual up up
Vlan10 10.0.0.2 YES manual up up
Vlan14 10.0.0.5 YES manual down down (el segmento de real Router-B -
Router-C)
Router-B#
6.- Verificamos OSPF en
Router-B:
Router-B#sh ip protocol
Routing Protocol is "ospf 1"
Outgoing
update filter list for all interfaces is not set
Incoming
update filter list for all interfaces is not set
Router ID
192.168.2.1
Number of
areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum
path: 4
Routing
for Networks:
10.0.0.0 0.0.0.3 area 0
10.0.0.4 0.0.0.3 area 0 (el
segmento de test Router-A - Router-C)
192.168.2.0 0.0.0.255 area 0
Passive
Interface(s):
Vlan2
Routing
Information Sources:
Gateway Distance Last Update
192.168.1.1 110 00:02:26
192.168.3.1 110 00:02:26
Distance:
(default is 110)
Router-B#
7.- Eliminamos temporalmente
la IP de la Vlan14 en Router-B:
Router-B#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router-B(config)#int vlan 14
Router-B(config-if)#no ip address
Router-B(config-if)#end
Router-B#
8.- Verificamos:
8.1.- Direcciones IP en el
Router-B:
Router-B#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0 unassigned YES unset up up (el segmento Router-B – Router-A)
FastEthernet1 unassigned YES unset down down (el segmento Router-B – Router-C)
FastEthernet2 unassigned YES unset up up (el segmento LAN 192.168.2.0/24)
FastEthernet3 unassigned YES unset down down
Vlan1 unassigned YES NVRAM up up
Vlan2 192.168.2.1 YES manual up up
Vlan10 10.0.0.2 YES manual up up
Vlan14 unassigned YES manual down down (el segmento de real Router-B - Router-C)
Router-B#
8.2.- Verificamos OSPF en
Router-B:
Router-B#sh ip protocol
*** IP Routing is NSF aware ***
Routing Protocol is “ospf 1”
Outgoing
update filter list for all interfaces is not set
Incoming
update filter list for all interfaces is not set
Router ID
192.168.2.1
Number of
areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum
path: 4
Routing
for Networks:
10.0.0.0 0.0.0.3 area 0
10.0.0.4 0.0.0.3 area 0 (sigue
estando declarada en OSPF pero no influye)
192.168.2.0 0.0.0.255 area 0
Passive
Interface(s):
Vlan2
Routing
Information Sources:
Gateway Distance Last Update
192.168.1.1 110 00:00:07
192.168.3.1 110 00:00:07
Distance:
(default is 110)
Router-B#
8.3.- Tabla de enrutamiento
en Router-B:
Router-B#sh 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, + - replicated route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C
10.0.0.0/30 is directly connected, Vlan10
L
10.0.0.2/32 is directly connected, Vlan10
O
10.0.0.4/30 [110/2] via 10.0.0.1, 00:00:55, Vlan10
O
192.168.1.0/24 [110/2] via 10.0.0.1, 00:38:54, Vlan10
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.2.0/24 is directly connected, Vlan2
L
192.168.2.1/32 is directly connected, Vlan2
O 192.168.3.0/24 [110/3] via 10.0.0.1,
00:00:56, Vlan10 (via
Router-C / Router-A)
Router-B#
9.- Resumen:
Para tener en cuenta: si el router tiene una
interface down con una IP configurada, esta participa igualmente del proceso
OSPF y su publicación tiene alcance dentro del
área en la que participe.
De haber un conflicto de IP duplicadas (detalle:
en un ambiente LAN estos conflictos son de ARP), los routers reclamarán
su “identifdad OSPF” (independientemente del
router-id) generando dentro del área un flooding del LSA del “rival” con un
tiempo (age) máximo, similar a un timeout, para
invalidarlo.
Esto nos coloca en la situación de ser cautos a
la hora de conectar un equipo en una red de producción, ya que ademas de
los logs nos genera una percepción erronea en las
tablas de enrutamiento, y si el router es una maqueta para reemplazar
otro en producción (por ejemplo el futuro
reemplazo de un equipo obsoleto) y tuviese una IP que se solape con un segmento
activo podemos causar una auto DoS (denegación de
servicio). Cosas del networking…
10.- Fuentes de referencia
para el troubleshooting:
Me tranquilizó que la respuesta estuviese en una
página que comience con “Complex” 😊
En el Issue 1 hay una explicación que me
aproxima a la causa del problema:
En esta página encontré otra explicación donde ya
especifica que pueden haber IP duplicadas en el area 0:
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/9237-9.html#wat
En esta página encontré el issue de que aunque la
interface esté down y la IP está configurada dispara el problema.
https://knowtoshare.wordpress.com/2012/05/31/ospf-inconsistent-ospf-route/
En estos libros encontré de que nunca se termina
de aprender OSPF…
(2023) Route to madness
Rosario, Argentina