Tabla de enrutamiento
no muestra rutas OSPF externas
Fecha: 31 de enero del 2023
Escenario
Este laboratorio está basado en un escenario real mucho más complejo, pero que por simplicidad se reduce
a tres switches layer 3 y un router Mikrotik simulando ser un nodo contenedor de Kubernetes (o como se llamen)
que aloja la red 172.16.0.0/24 repartida en hasta 254 hosts /32, y que publica estos por BGP contra uno de los
switches layer 3 que lo redistribuye en OSPF.
No vamos a entrar mucho en la teoría de por qué los Kubernetes (o como se llamen) usan BGP pero básicamente
es porque pueden crearse dinámicamente en N nodos físicos distribuídos en la red, y por eso se muestran como /32
cuando se publican al levantar. Y al que quiera usar BGP en toda la red, bueno, le deseo la mejor suerte en ello.
El problema en cuestión es que desde una red conectada a uno de los switches layer 3 (puntualmente el Switch-L3-B) no
se pueden alcanzar los Kubernetes (o como se llamen) si no es mediante una ruta estática 172.16.0.0/24 vía Switch-L3-C
(que se configuró “como para zafar hasta que lo vea Ernesto”), cuando debería aprenderse por OSPF como en el resto
de los switches de la topología.
Y allá vamos…
1.- Verificación inicial de vecindario OSPF:
1.1.-
En Switch-L3-A:
Switch-L3-A#sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.1.2
255 FULL/DR 00:00:36 192.168.1.2 Vlan1 (Switch-L3-B)
192.168.1.3 1
FULL/BDR 00:00:38 192.168.1.3 Vlan1 (Switch-L3-C)
Switch-L3-A#
1.2.-
En Switch-L3-B:
Switch-L3-B#sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.1.1 1
FULL/DROTHER
:00:36 192.168.1.1 Vlan1 (Switch-L3-A)
192.168.1.3 1
FULL/BDR 00:00:38 192.168.1.3 Vlan1 (Switch-L3-C)
Switch-L3-B#
1.3.-
En Switch-L3-C:
Switch-L3-C#sh ip ospf neighbor
Neighbor ID
Pri State Dead Time Address Interface
192.168.1.1 1
FULL/DROTHER :00:37 192.168.1.1 Vlan1 (Switch-L3-A)
192.168.1.2
255 FULL/DR 00:00:36 192.168.1.2 Vlan1 (Switch-L3-B)
Switch-L3-C#
2.- Verificamos rutas:
2.1.-
En Switch-L3-A:
Switch-L3-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, + - replicated route
Gateway of last resort is not set
172.16.0.0/32 is subnetted, 3 subnets
O E2 172.16.0.1 [110/1] via
192.168.1.3, 00:09:28, Vlan1 (BGP redistribuído en
OSPF)
O E2 172.16.0.2 [110/1] via
192.168.1.3, 00:09:28, Vlan1
O E2 172.16.0.3 [110/1] via
192.168.1.3, 00:09:28, Vlan1
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, Vlan1 (backbone
OSPF)
L
192.168.1.1/32 is directly connected, Vlan1
O
192.168.2.0/24 [110/2] via 192.168.1.3, 00:07:12, Vlan1 (segmento BGP)
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.10.0/24 is directly connected, Vlan10 (LAN
Switch-L3-A)
L
192.168.10.1/32 is directly connected, Vlan10
O
192.168.20.0/24 [110/2] via 192.168.1.2, 00:03:29, Vlan1 (LAN Switch-L3-B)
O 192.168.30.0/24 [110/2] via 192.168.1.3, 00:05:33, Vlan1 (LAN Switch-L3-C)
Switch-L3-A#
2.2.-
En Switch-L3-B:
Switch-L3-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, H - NHRP, l - LISP
+
- replicated route, % - next hop override
Gateway of last resort is not set
172.16.0.0/16 is subnetted, 1 subnets
S 172.16.0.0/24 [1/0] via
192.168.1.3 (ruta configurada a mano para poder
operar)
192.168.1.0/24 is variably
subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, Vlan1 (backbone
OSPF)
L
192.168.1.2/32 is directly connected, Vlan1
S 192.168.2.0/24 [1/0] via 192.168.1.3 (segmento
BGP configurado a mano)
O 192.168.10.0/24 [110/2] via 192.168.1.1, 00:04:55, Vlan1 (LAN Switch-L3-A)
192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.20.0/24 is directly connected, Vlan20 (LAN
Switch-L3-B)
L
192.168.20.1/32 is directly connected, Vlan20
O
192.168.30.0/24 [110/2] via 192.168.1.3, 00:02:27, Vlan1 (LAN Switch-L3-C)
Switch-L3-B#
2.3.-
En Switch-L3-C:
Switch-L3-C#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
172.16.0.0/32 is subnetted, 3 subnets
B 172.16.0.1 [200/0] via 192.168.2.2,
00:10:18
B 172.16.0.2 [200/0] via 192.168.2.2,
00:10:18
B 172.16.0.3 [200/0] via 192.168.2.2,
00:10:18
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, Vlan1 (backbone
OSPF)
L
192.168.1.3/32 is directly connected, Vlan1
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.2.0/24 is directly connected, Vlan2 (segmento
BGP)
L
192.168.2.1/32 is directly connected, Vlan2
O
192.168.10.0/24 [110/2] via 192.168.1.1, 00:08:55, Vlan1 (LAN Switch-L3-A)
O 192.168.20.0/24 [110/2] via 192.168.1.2, 00:04:42, Vlan1 (LAN Switch-L3-B)
192.168.30.0/24 is variably subnetted, 2
subnets, 2 masks
C
192.168.30.0/24 is directly connected, Vlan30 (LAN
Switch-L3-C)
L
192.168.30.1/32 is directly connected, Vlan30
Switch-L3-C#
2.4.- El servidor/nodo que aloja los Kubernetes (o como se llamen):
El router tiene una única ruta por defecto a través de la interface VLAN 2 del Switch-L3-B.
3.- Eliminamos la ruta estática a la red 172.16.0.0/24 para trabajar
únicamente con el OSPF:
Switch-L3-B(config)#no ip route 172.16.0.0 255.255.255.0
192.168.2.2
Switch-L3-B(config)#
4.- Verificamos:
Switch-L3-B#sh ip route (no existen rutas a
172.16.x.x)
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
+
- replicated route, % - next hop override
Gateway of last resort is not set
192.168.1.0/24
is variably subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, Vlan1 (backbone
OSPF)
L
192.168.1.2/32 is directly connected, Vlan1
S
192.168.2.0/24 [1/0] via 192.168.1.3
O 192.168.10.0/24
[110/2] via 192.168.1.1, 00:15:19, Vlan1
192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.20.0/24 is directly connected, Vlan20
L
192.168.20.1/32 is directly connected, Vlan20
O 192.168.30.0/24 [110/2] via 192.168.1.3, 00:12:51, Vlan1
Switch-L3-B#
5.- Verificación OSPF para ver si aprendió las rutas:
Switch-L3#sh ip ospf route (no aparecen las rutas
externas)
OSPF Router with ID (192.168.1.2) (Process ID 1)
Base Topology (MTID 0)
Area BACKBONE(0)
Intra-area Route List
*
192.168.1.0/24, Intra, cost 1, area 0, Connected
via 192.168.1.2, Vlan1
*
192.168.2.0/24, Intra, cost 2, area 0
via 192.168.1.3, Vlan1
*> 192.168.10.0/24, Intra, cost 2, area 0
via 192.168.1.1, Vlan1
*
192.168.20.0/24, Intra, cost 1, area 0, Connected
via 192.168.20.1, Vlan20
*> 192.168.30.0/24, Intra, cost 2, area 0
via 192.168.1.3, Vlan1
Intra-area Router Path List
i 192.168.1.3 [1] via 192.168.1.3, Vlan1, ASBR,
Area 0, SPF 49
Switch-L3#
Switch-L3-B#sh ip ospf database
OSPF Router with ID (192.168.1.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
192.168.1.1 192.168.1.1 1495 0x80000003 0x00FA87 1
192.168.1.2 192.168.1.2 632 0x80000016 0x00D299 1
192.168.1.3 192.168.1.3 44 0x80000004 0x004FAD 2
Net Link States (Area 0)
Link ID
ADV Router Age Seq# Checksum
192.168.1.2
192.168.1.2 1454 0x80000002 0x00C551
Type-5 AS External
Link States
Link ID
ADV Router Age Seq# Checksum Tag
172.16.0.1 192.168.1.3 39
0x80000003 0x00D642 0 (las aprendió pero no las publica)
172.16.0.2
192.168.1.3 39 0x80000003 0x00CC4B 0
172.16.0.3
192.168.1.3 39 0x80000003 0x00C254 0
Switch-L3-B#
6.- Comenzamos el análisis del OSPF:
Switch-L3#debug ip routing
IP routing debugging is on
Switch-L3-B#debug ip ospf events
OSPF events debugging is on
Switch-L3-B#debug ip ospf sfp
OSPF SPF debugging is on
OSPF SPF intra debugging is on
OSPF SPF inter debugging is on
OSPF SPF external debugging is on
Switch-L3-B#
7.- Eliminamos la ruta estática a la red 2:
Switch-L3-B#conf t
Enter configuration commands, one per
line. End with CNTL/Z.
Switch-L3-B(config)#no ip route 192.168.2.0 255.255.255.0
192.168.1.3
Switch-L3-B(config)#
Jan 31 13:52:53.820: RT: del
192.168.2.0 via 192.168.1.3, static metric [1/0]
Jan 31 13:52:53.820: RT: delete network route
to 192.168.2.0/24
Jan 31 13:52:53.820: RT: updating ospf 192.168.2.0/24 (0x0) :
via 192.168.1.3 Vl1 0
1048578
Jan 31 13:52:53.820: RT: add 192.168.2.0/24 via
192.168.1.3, ospf metric [110/2]
Jan 31 13:53:09.315: RT: updating ospf
172.16.0.3/32 (0x0) :
via 192.168.1.3 Vl1 0
1048578
Jan 31 13:53:09.315: RT: add 172.16.0.3/32 via 192.168.1.3, ospf metric [110/1]
Jan 31 13:53:09.318: RT: updating ospf
172.16.0.2/32 (0x0) :
via 192.168.1.3 Vl1 0
1048578
Jan 31 13:53:09.318: RT: add 172.16.0.2/32 via 192.168.1.3, ospf metric [110/1]
Jan 31 13:53:09.318: RT: updating ospf
172.16.0.1/32 (0x0) :
via 192.168.1.3 Vl1 0 1048578
Jan 31 13:53:09.318: RT: add 172.16.0.1/32 via 192.168.1.3, ospf metric [110/1]
8.- Verificamos:
8.1.- En la tabla de enrutamiento:
Switch-L3-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
172.16.0.0/32 is subnetted, 3 subnets
O E2 172.16.0.1 [110/1]
via 192.168.1.3, 00:07:48, Vlan1 (se agregaron las
rutas vía OSPF)
O E2 172.16.0.2 [110/1] via 192.168.1.3, 00:07:48, Vlan1
O E2 172.16.0.3 [110/1] via 192.168.1.3, 00:07:48, Vlan1
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 192.168.1.3, 00:14:25, Vlan1 (se agregó la ruta vía OSPF)
O 192.168.10.0/24 [110/2] via 192.168.1.1,
00:15:19, Vlan1
192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.20.0/24 is directly connected, Vlan20
L
192.168.20.1/32 is directly connected, Vlan20
O 192.168.30.0/24 [110/2] via 192.168.1.3, 00:12:51, Vlan1
Switch-L3-A#
8.2.-
En el OSPF:
Switch-L3#sh
ip ospf route
OSPF Router with ID (192.168.1.2) (Process ID 1)
Base Topology (MTID 0)
Area BACKBONE(0)
Intra-area Route List
*
192.168.1.0/24, Intra, cost 1, area 0, Connected
via 192.168.1.2, Vlan1
*> 192.168.2.0/24, Intra, cost 2, area 0
via 192.168.1.3, Vlan1
*> 192.168.10.0/24, Intra, cost 2, area 0
via 192.168.1.1, Vlan1
* 192.168.20.0/24,
Intra, cost 1, area 0, Connected
via 192.168.20.1, Vlan20
*> 192.168.30.0/24, Intra, cost 2, area 0
via 192.168.1.3, Vlan1
Intra-area Router Path List
i 192.168.1.3 [1] via 192.168.1.3, Vlan1, ASBR,
Area 0, SPF 49
External
Route List
*> 172.16.0.1/32, Ext2, cost 1, tag 0
via 192.168.1.3, Vlan1
*> 172.16.0.2/32, Ext2, cost 1, tag 0
via 192.168.1.3, Vlan1
*> 172.16.0.3/32, Ext2, cost 1, tag 0
via 192.168.1.3, Vlan1
Switch-L3#
9.- Contraprueba agregando la ruta estática nuevamente:
Switch-L3-B#conf t
Enter configuration commands, one per
line. End with CNTL/Z.
Switch-L3-B(config)#ip route 192.168.2.0 255.255.255.0
192.168.1.3
Switch-L3-B(config)#
Jan 31 13:47:27.574: OSPF-1 INTER: Check and
generate summary LSA into all areas
Jan 31 13:47:27.574: OSPF-1 EXTER: Started
Building Type 5 External Routes
Jan 31 13:47:27.574: OSPF-1 EXTER: Start
processing Type 5 External LSA
172.16.0.1, mask 255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: adv_rtr 192.168.1.3, age 799, seq 0x80000001,
metric 1, metric-type 2, fw-addr
192.168.2.2
Jan 31 13:47:27.574: OSPF-1 EXTER: More
specific non-OSPF route to forwarding address
Jan 31 13:47:27.574: OSPF-1 EXTER: Add forward address unreachable 192.168.2.2,
allowed types Intra and Inter, to watched queue
Jan 31 13:47:27.574: OSPF-1 EXTER: Start
processing Type 5 External LSA 172.16.0.2,
mask 255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: adv_rtr 192.168.1.3, age 799, seq 0x80000001,
metric 1, metric-type 2, fw-addr 192.168.2.2
Jan 31 13:47:27.574: OSPF-1 EXTER: More
specific non-OSPF route to forwarding address
Jan 31 13:47:27.574: OSPF-1 EXTER: Start
processing Type 5 External LSA 172.16.0.3,
mask 255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: adv_rtr 192.168.1.3, age 798, seq 0x80000001,
metric 1, metric-type 2, fw-addr 192.168.2.2
Jan 31 13:47:27.574: OSPF-1 EXTER: More
specific non-OSPF route to forwarding address
Jan 31 13:47:27.574: OSPF-1 EXTER: Started
Building Type 7 External Routes
Jan 31 13:47:27.574: OSPF-1 EXTER: Entered
External route sync for area dummy area
Jan 31 13:47:27.574: OSPF-1 EXTER: Entered
External route sync for area dummy area
Jan 31 13:47:27.574: OSPF-1 EXTER: Deleted external route
172.16.0.1/255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: Deleted external route
172.16.0.2/255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: Deleted external route
172.16.0.3/255.255.255.255
Jan 31 13:47:27.574: OSPF-1 EXTER: Entered NSSA
route sync for area 0
Jan 31 13:47:27.574: OSPF-1 EXTER: Entered NSSA
route sync for area 0
Switch-L3-B#
10.- Verificamos:
10.1.- En la tabla de enrutamiento:
Switch-L3-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, H - NHRP, l - LISP
+
- replicated route, % - next hop override
Gateway of last resort is not set
192.168.1.0/24
is variably subnetted, 2 subnets, 2 masks (desaparecen
las rutas 172.16.0.x)
C
192.168.1.0/24 is directly connected, Vlan1
L
192.168.1.2/32 is directly connected, Vlan1
S 192.168.2.0/24 [1/0] via 192.168.1.3
O
192.168.10.0/24 [110/2] via 192.168.1.1, 00:12:36, Vlan1
192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.20.0/24 is directly connected, Vlan20
L
192.168.20.1/32 is directly connected, Vlan20
O 192.168.30.0/24 [110/2] via 192.168.1.3, 00:10:08, Vlan1
Switch-L3-B#
11.- Resumen:
En el escenario real
probablemente la ruta estática quedó como configuración residual por un
problema de licencias en el switch
y que
bajó el proceso OSPF y hubo que improvisar con rutas estáticas.
Para poder alcanzar las redes 172.16.0.x redistribuídas en OSPF, es necesario que el gateway a estas pertenezca a una red
aprendida por OSPF, o directamente que no haya rutas con mejor métricas a esta red (hablamos de la 192.168.2.0/24).
La existencia de una ruta estática al mencionado segmento (como en el caso de este escenario) hace que dichas redes no
sean procesadas por OSPF ni instaladas en la tabla de enrutamiento.
12.- Detalle post resumen:
Como detalle dejado para luego de reflexionar por que no eran alcanzables la redes 17216.0.x, dejamos documentado de que
no es necesario publicar en el OSPF la red 192.168.2.0/24 para que el resto de los switches aorendan las primeras.
Por eso en el resumen del laboratorios se aclara “o directamente que no haya rutas con mejor métricas a esta red” para demostrar
esto hacemos la siguiente prueba:
12.1.- Verificamos la existencia de la ruta del segmento BGP/OSPF:
Switch-L3-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, + - replicated route
Gateway of last resort is not set
172.16.0.0/32
is subnetted, 3 subnets
O E2 172.16.0.1 [110/1]
via 192.168.1.3, 00:09:48, Vlan1
O E2 172.16.0.2 [110/1]
via 192.168.1.3, 00:09:48, Vlan1
O E2 172.16.0.3 [110/1] via 192.168.1.3, 00:09:48, Vlan1
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 192.168.1.3, 00:00:05, Vlan1 (vemos publicada la
ruta BGP/OSPF)
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.10.0/24 is directly connected, Vlan10
L
192.168.10.1/32 is directly connected, Vlan10
O
192.168.20.0/24 [110/2] via 192.168.1.2, 00:03:29, Vlan1
O 192.168.30.0/24 [110/2] via 192.168.1.3, 00:05:33, Vlan1
Switch-L3-A #
12.2.- Dejamos de publicar el segmento en el OSPF:
Switch-L3-C#conf t
Enter configuration commands, one per
line. End with CNTL/Z.
Switch-L3-C(config)#router ospf 1
Switch-L3-C (config-router)#no network 192.168.2.0 0.0.0.255 area 0
Switch-L3-C (config-router)#end
Switch-L3-C #
12.3.- Verificamos:
Switch-L3-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, + - replicated route
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
O E2 172.16.0.1/32
[110/1] via 192.168.1.3, 00:07:18, Vlan1 (siguen
publicandose las rutas redistribuídas)
O E2 172.16.0.2/32
[110/1] via 192.168.1.3, 00:07:18, Vlan1
O E2 172.16.0.3/32 [110/1] via 192.168.1.3, 00:07:18, Vlan1
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 (ya no está publicada la ruta a la red
192.168.2.0/24)
192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.10.0/24 is directly connected, Vlan10
L
192.168.10.1/32 is directly connected, Vlan10
O
192.168.20.0/24 [110/2] via 192.168.1.2, 00:03:29, Vlan1
O 192.168.30.0/24 [110/2] via 192.168.1.3,
00:05:33, Vlan1
Switch-L3-A#
¿ Por que entonces se publica en OSPF la red 192.168.2.0/24 ? es porque existen otros servers en esa red,
también
para alcanzar y administrar el nodo que aloja los fucking Kubernetes (o como se llamen) y también
porque queda prolijo y educado publicarla.
13.- Configuración de los equipos:
13.1.- Switch-L3-A:
Switch-L3-A#sh run (sólo lo más relevante)
!
ip routing
!
- interfaces físicas en las VLANs correspondientes -
!
interface Vlan1
ip address
192.168.1.1 255.255.255.0
!
interface Vlan10
ip address 192.168.10.1 255.255.255.0
!
router ospf 1
network 192.168.1.0 0.0.0.255 area 0 (backbone inter-switches)
network 192.168.10.0 0.0.0.255 area 0
!
Switch-L3-A#
13.2.-
Switch-L3-B:
Switch-L3-B#sh run (sólo lo más relevante)
!
ip routing
!
- interfaces físicas en las VLANs correspondientes -
!
interface Vlan1
ip address 192.168.1.2 255.255.255.0
ip ospf priority 255 (fuerza a ser
el DR)
!
interface Vlan20
ip address 192.168.20.1 255.255.255.0
!
router ospf 1
network 192.168.1.0 0.0.0.255 area 0 (backbone inter-switches)
network 192.168.2.0 0.0.0.255 area 0
!
ip route 192.168.2.0 255.255.255.0 192.168.1.3
!
Switch-L3-B#
13.3.-
Switch-L3-B:
Switch-L3-C#sh run (sólo lo más relevante)
!
ip routing
!
- interfaces físicas en las VLANs correspondientes -
!
interface Vlan1
ip address 192.168.1.3 255.255.255.0
!
interface Vlan2
ip address 192.168.2.1 255.255.255.0
!
interface Vlan30
ip address 192.168.30.1 255.255.255.0
router ospf 1
router-id 192.168.1.3
redistribute bgp 1234 subnets
network 192.168.1.0 0.0.0.255 area 0 (backbone inter-switches)
network 192.168.2.0 0.0.0.255 area 0 (VLAN de servers y segmento BGP)
network 192.168.30.0 0.0.0.255 area 0
!
router bgp 1234
bgp log-neighbor-changes
bgp redistribute-internal (al ser una topología iBGP permite que se redistribuya en OSPF)
neighbor 192.168.2.2 remote-as 1234 (el switch Switch-L3-C)
!
Switch-L3-C#
13.4.- Mikrotik que simulamos los Kubernetes (o como se llamen):
13.4.1.- Interfaces:
13.4.2.- Instancia BGP:
13.4.3.- Declaramos las redes a publicar:
13.4.4.- Declaramos el Switch-L3-B como peer:
(2023) ¡
Por dios ! la ruta está
trabada y fría…
Rosario, Argentina