EIGRP Parte 3: Configuração básica

(Terminando a trilogia)

Para fecharmos o assunto, pelo menos por enquanto, vamos ver como configurar o EIGRP.

Usaremos  a topologia abaixo, onde temos três caminhos de R1 para R5, sendo que de R1 para R2 temos banda e delay padrão, de R1 para R3 temos o delay de 110 e autenticação, e de R1 para R4 estaremos fazendo a sumarização das rotas.

Configuração inicial, para referência.

R1
hostname R1
interface Loopback0
  ip address 10.1.0.1 255.255.255.0
interface Loopback1
  ip address 10.1.1.1 255.255.255.0
interface Loopback2
  ip address 10.1.2.1 255.255.255.0
interface Ethernet0/0
  ip address 192.168.0.2 255.255.255.252
interface Ethernet0/1
  ip address 192.168.1.2 255.255.255.252
  delay 110
interface Ethernet0/2
  ip address 192.168.2.2 255.255.255.252

R2
hostname R2
interface Ethernet0/0
  ip address 192.168.0.1 255.255.255.252
interface Ethernet0/1
  ip address 192.168.10.1 255.255.255.252
router eigrp 10
  network 192.168.0.0 0.0.0.3
  network 192.168.10.0 0.0.0.3

R3
hostname R3
interface Ethernet0/0
  ip address 192.168.1.1 255.255.255.252
  ip authentication mode eigrp 10 md5
  ip authentication key-chain eigrp 10 EIGRPPASS
interface Ethernet0/1
  ip address 192.168.11.1 255.255.255.252
  ip authentication mode eigrp 10 md5
  ip authentication key-chain eigrp 10 EIGRPPASS
router eigrp 10
  network 192.168.1.0 0.0.0.3
  network 192.168.11.0 0.0.0.3
key chain EIGRPPASS
  key 1
   key-string cisco123

R4
hostname R4
interface Ethernet0/0
  ip address 192.168.2.1 255.255.255.252
interface Ethernet0/1
  ip address 192.168.12.1 255.255.255.252
router eigrp 10
  network 192.168.2.0 0.0.0.3
  network 192.168.12.0 0.0.0.3
R5
hostname R5
interface Loopback0
  ip address 10.2.0.1 255.255.255.0
interface Loopback1
  ip address 10.2.1.1 255.255.255.0
interface Loopback2
  ip address 10.2.2.1 255.255.255.0
interface Ethernet0/0
  ip address 192.168.10.2 255.255.255.252
interface Ethernet0/1
  ip address 192.168.11.2 255.255.255.252
interface Ethernet0/2
  ip address 192.168.12.2 255.255.255.252

Existem duas formas de configurar o EIGRP: modo clássico e modo nomeado.

R1 será configurado usando o modo clássico (como R2, R3 e R4 foram configurados), e R5 será configurado com o modo nomeado.

Configuração R1

Vamos habilitar o EIGRP especificando o AS 10. O AS precisa ser o mesmo entre os roteadores que formarão vizinhança. Na sequência devemos especificar, com o comando network, em quais interfaces o EIGRP será habilitado. Se não for especificada a máscara (wildcard) o EIGRP considera a máscara padrão (classful).

conf t
router eigrp 10
  network 10.0.0.0
  network 192.168.0.0 0.0.255.255

Com essa configuração R1 já formará vizinhança com R2 e R4. A vizinhança com R3 ainda não vai funcionar porque precisamos configurar a autenticação.

R1#show ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(10)
H   Address                 Interface              Hold Uptime   SRTT   RTO  Q  Seq
                                                    (sec)         (ms)       Cnt Num
2   192.168.2.1             Et0/2                    10 00:05:56   12   100  0  39
1   192.168.0.1             Et0/0                    11 00:05:56    9   100  0  37
R1#

Para incrementar nosso exemplo, vamos configurar a autenticação na interface E0/1 (link com R3), utilizando key chain, e fazer a sumarização manual na interface E0/2 (link com R4). Aliás esta é uma vantagem do EIGRP, que nos permite fazer a sumarização em qualquer ponto da rede (diferente do OSPF).

conf t
key chain EIGRPPASS
key 1
   key-string cisco123
interface Ethernet0/1
  ip authentication mode eigrp 10 md5
  ip authentication key-chain eigrp 10 EIGRPPASS
interface Ethernet0/2
  ip summary-address eigrp 10 10.1.0.0 255.255.0.0

Agora sim podemos ver os 3 neighbors (R2, R3 e R4).

R1#show ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(10)
H   Address                 Interface              Hold Uptime   SRTT   RTO  Q  Seq
                                                   (sec)         (ms)       Cnt Num
2   192.168.2.1             Et0/2                    12 00:00:18  943  5000  0  72
0   192.168.1.1             Et0/1                    12 00:18:41   10   100  0  57
1   192.168.0.1             Et0/0                    12 00:57:41    7   100  0  55
R1#

Também observe que foi criada uma entrada na tabela de roteamento de R1 apontando para Null0, por conta da sumarização.

R1#show ip route eigrp
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, 7 subnets, 3 masks
D        10.1.0.0/16 is a summary, 00:00:05, Null0
       192.168.10.0/30 is subnetted, 1 subnets
D        192.168.10.0 [90/307200] via 192.168.0.1, 00:59:29, Ethernet0/0
       192.168.11.0/30 is subnetted, 1 subnets
D        192.168.11.0 [90/309760] via 192.168.1.1, 00:20:30, Ethernet0/1
       192.168.12.0/30 is subnetted, 1 subnets
D        192.168.12.0 [90/307200] via 192.168.2.1, 00:02:06, Ethernet0/2
R1#

Configuração R5

Vamos fazer as mesmas configurações em R5, mas neste caso usaremos o modo “named”.

conf t
key chain EIGRPPASS
  key 1
   key-string cisco123
router eigrp MyEIGRP
  address-family ipv4 unicast autonomous-system 10
   af-interface Ethernet0/2
    summary-address 10.2.0.0 255.255.0.0
   exit-af-interface
   af-interface Ethernet0/1
    authentication mode md5
    authentication key-chain EIGRPPASS
   exit-af-interface
   topology base
   exit-af-topology
   network 10.2.0.0 0.0.255.255
   network 192.168.0.0 0.0.255.255
  exit-address-family

Podemos fazer as mesmas verificações que fizemos em R1.

R5#show ip eigrp neighbors
EIGRP-IPv4 VR(MyEIGRP) Address-Family Neighbors for AS(10)
H   Address                 Interface              Hold Uptime   SRTT   RTO  Q  Seq
                                                    (sec)         (ms)       Cnt Num
2   192.168.11.1            Et0/1                    14 00:00:45    2   100  0  63
1   192.168.12.1            Et0/2                    10 00:02:35    9   100  0  81
0   192.168.10.1            Et0/0                    14 00:02:36    9   100  0  61
R5#

R5#show ip route eigrp
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, 11 subnets, 3 masks
D        10.1.0.0/16 [90/4096000] via 192.168.12.1, 00:02:48, Ethernet0/2
D        10.1.0.0/24 [90/4096000] via 192.168.11.1, 00:00:58, Ethernet0/1
                      [90/4096000] via 192.168.10.1, 00:00:58, Ethernet0/0
D        10.1.1.0/24 [90/4096000] via 192.168.11.1, 00:00:58, Ethernet0/1
                      [90/4096000] via 192.168.10.1, 00:00:58, Ethernet0/0
D        10.1.2.0/24 [90/4096000] via 192.168.11.1, 00:00:58, Ethernet0/1
                      [90/4096000] via 192.168.10.1, 00:00:58, Ethernet0/0
D        10.2.0.0/16 is a summary, 00:02:52, Null0
       192.168.0.0/30 is subnetted, 1 subnets
D        192.168.0.0 [90/1536000] via 192.168.10.1, 00:00:58, Ethernet0/0
       192.168.1.0/30 is subnetted, 1 subnets
D        192.168.1.0 [90/1536000] via 192.168.11.1, 00:00:58, Ethernet0/1
       192.168.2.0/30 is subnetted, 1 subnets
D        192.168.2.0 [90/1536000] via 192.168.12.1, 00:00:58, Ethernet0/2
R5#

O comando debug eigrp packets pode ser usado para confirmar que temos autenticação na interface E0/1.

R1#debug eigrp packets
     (UPDATE, REQUEST, QUERY, REPLY, HELLO, UNKNOWN, PROBE, ACK, STUB, SIAQUERY, SIAREPLY)
EIGRP Packet debugging is on
R1#
*Sep  3 19:21:42.800: EIGRP: Received HELLO on Et0/2 - paklen 20 nbr 192.168.2.1
*Sep  3 19:21:42.801:   AS 10, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0
*Sep  3 19:21:44.337: EIGRP: Received HELLO on Et0/0 - paklen 20 nbr 192.168.0.1
*Sep  3 19:21:44.337:   AS 10, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0
*Sep  3 19:21:44.596: EIGRP: Sending HELLO on Et0/2 - paklen 20
*Sep  3 19:21:44.596:   AS 10, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0
*Sep  3 19:21:44.763: EIGRP: received packet with MD5 authentication, key id = 1
*Sep  3 19:21:44.763: EIGRP: Received HELLO on Et0/1 - paklen 60 nbr 192.168.1.1
*Sep  3 19:21:44.763:   AS 10, Flags 0x0:(NULL), Seq 0/0 interfaceQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/0

Mais informações e exemplos neste link.

Até a próxima.