Configuración de GRE en IPSec entre un router del IOS de Cisco y un concentrador VPN 5000 que usa ruteo estático
Contenido
Introducción
Este documento describe cómo configurar la encapsulación de ruteo genérico (GRE) sobre IPSec entre un Cisco VPN 5000 Series Concentrator y un router Cisco que ejecuta el software Cisco IOS®. La función GRE sobre IPSec se introduce en la versión de software del VPN 5000 Concentrator 6.0(19).
En este ejemplo, el ruteo estático se utiliza para rutear paquetes a través del túnel.
Prerequisites
Requirements
No hay requisitos específicos para este documento.
Componentes Utilizados
La información que contiene este documento se basa en las siguientes versiones de software y hardware.
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Versión 12.2(3) del software Cisco IOS
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Software Cisco VPN 5000 Concentrator versión 6.0(19)
La información que contiene este documento se creó a partir de los dispositivos en un ambiente de laboratorio específico. Todos los dispositivos que se utilizan en este documento se pusieron en funcionamiento con una configuración verificada (predeterminada). If your network is live, make sure that you understand the potential impact of any command.
Convenciones
For more information on document conventions, refer to the Cisco Technical Tips Conventions.
Configurar
En esta sección encontrará la información para configurar las funciones descritas en este documento.
Nota: Para encontrar información adicional sobre los comandos utilizados en este documento, utilice la Command Lookup Tool (sólo para clientes registrados) .
Diagrama de la red
Este documento utiliza la configuración de red que se muestra en el siguiente diagrama.
GRE sobre IPSec se configura entre el router 1720-1 que ejecuta el software Cisco IOS y el concentrador VPN 5002. Detrás del router y del concentrador VPN, hay varias redes que se anuncian a través de OSPF (Open Shortest Path First). OSPF se ejecuta dentro del túnel GRE entre el router y el concentrador VPN.
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Estas redes están detrás del router 1720-1.
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10.1.1.0/24
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10.1.2.0/24
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10.1.3.0/24
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Estas redes están detrás del concentrador VPN 5002.
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20.1.1.0/24
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20.1.2.0/24
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20.1.3.0/24
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Configuraciones
Este documento usa estas configuraciones.
Nota: Con las versiones 12.2(13)T y posteriores del software del IOS de Cisco (códigos T-train de números más altos, códigos 12.3 y posteriores), debe aplicar el mapa criptográfico IPSec configurado sólo a la interfaz física. Ya no es necesario aplicar el mapa criptográfico en la interfaz de túnel GRE. El uso del mapa criptográfico en las interfaces física y de túnel cuando se utiliza Cisco IOS Software Releases 12.2.(13)T y posteriores aún debería funcionar, pero Cisco Systems recomienda que aplique el mapa criptográfico sólo en la interfaz física.
| Router 1720-1 |
|---|
Current configuration : 1305 bytes ! version 12.2 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname 1720-1 ! no logging buffered no logging monitor enable secret 5 $1$vIzI$RqD0LqlqbSFCCjVELFLfH/ ! memory-size iomem 15 ip subnet-zero no ip domain-lookup ! ip audit notify log ip audit po max-events 100 ip ssh time-out 120 ip ssh authentication-retries 3 ! crypto isakmp policy 1 hash md5 authentication pre-share crypto isakmp key cisco123 address 172.16.172.21 ! ! crypto ipsec transform-set myset esp-des esp-md5-hmac mode transport ! crypto map vpn 10 ipsec-isakmp set peer 172.16.172.21 set transform-set myset match address 102 ! cns event-service server ! ! ! interface Tunnel0 ip address 50.1.1.1 255.255.255.252 tunnel source FastEthernet0 tunnel destination 172.16.172.21 crypto map vpn ! interface FastEthernet0 ip address 172.16.172.39 255.255.255.240 speed auto crypto map vpn ! interface Serial0 ip address 10.1.1.2 255.255.255.0 encapsulation ppp ! ip classless ip route 0.0.0.0 0.0.0.0 172.16.172.33 ip route 10.1.0.0 255.255.0.0 10.1.1.1 ip route 20.1.0.0 255.255.0.0 Tunnel0 no ip http server ! access-list 102 permit gre host 172.16.172.39 host 172.16.172.21 ! line con 0 line aux 0 line vty 0 4 password cisco login ! no scheduler allocate end |
| Concentrador VPN 5002 |
|---|
[ General ] VPNGateway = 172.16.172.17 EthernetAddress = 00:05:32:3e:90:40 DeviceType = VPN 5002/8 Concentrator ConfiguredOn = Timeserver not configured ConfiguredFrom = Command Line, from Console [ IKE Policy ] Protection = SHA_DES_G1 Protection = MD5_DES_G2 Protection = MD5_DES_G1 [ Tunnel Partner VPN 1 ] KeyLifeSecs = 3500 KeepaliveInterval = 120 TunnelType = GREinIPSec InactivityTimeout = 120 Transform = ESP(MD5,DES) BindTo = "Ethernet 1:0" SharedKey = "cisco123" Certificates = Off Mode = Main KeyManage = Reliable Partner = 172.16.172.39 [ IP VPN 1 ] HelloInterval = 10 SubnetMask = 255.255.255.252 IPAddress = 50.1.1.2 DirectedBroadcast = Off Numbered = On Mode = Routed [ IP Ethernet 1:0 ] Mode = Routed SubnetMask = 255.255.255.240 IPBroadcast = 172.16.172.32 IPAddress = 172.16.172.21 [ IP Ethernet 0:0 ] Mode = Routed IPBroadcast = 20.1.1.255 SubnetMask = 255.255.255.0 IPAddress = 20.1.1.1 [ Logging ] Level = Debug LogToAuxPort = On Enabled = On [ Ethernet Interface Ethernet 0:0 ] DUPLEX = half SPEED = 10meg [ IP Static ] 0.0.0.0 0.0.0.0 20.1.1.5 1 10.1.1.0 255.255.255.0 VPN 1 1 10.1.2.0 255.255.255.0 VPN 1 1 10.1.3.0 255.255.255.0 VPN 1 1 Configuration size is 1696 out of 65500 bytes. |
Verificación
En esta sección encontrará información que puede utilizar para confirmar que su configuración esté funcionando correctamente.
La herramienta Output Interpreter (sólo para clientes registrados) permite utilizar algunos comandos “show” y ver un análisis del resultado de estos comandos.
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Estos comandos se pueden ejecutar en el router Cisco IOS.
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show crypto isakmp sa: muestra todas las asociaciones de seguridad (SA) actuales de Internet Security Association and Key Management Protocol (ISAKMP).
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show crypto ipsec sa—Muestra todas las SA IPSec actuales.
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show crypto engine connection active—Muestra el contador de cifrado/descifrado de paquetes para cada SA IPSec.
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Puede ejecutar estos comandos en el concentrador VPN 5002.
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show system log buffer—Muestra información básica de syslog.
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vpn trace dump: muestra información detallada sobre los procesos de VPN.
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Troubleshoot
En esta sección encontrará información que puede utilizar para solucionar problemas de configuración.
Comandos para resolución de problemas
Nota: Antes de ejecutar los comandos debug, consulte Información Importante sobre Comandos Debug.
Puede ejecutar estos comandos en el router Cisco IOS.
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debug crypto isakmp: muestra información detallada sobre la negociación de la fase I (modo principal) del Intercambio de claves de Internet (IKE).
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debug crypto ipsec—Muestra información detallada sobre la negociación IKE fase II (modo rápido).
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debug crypto engine: depura el cifrado/descifrado de paquetes y el proceso Diffie-Hellman (DH).
Ejemplo de resultado del comando debug
Aquí se muestra un ejemplo de salida de depuración para el router y el concentrador VPN.
Depuraciones en el router Cisco IOS
Aquí se muestra la salida de los comandos debug crypto isakmp y debug crypto ipsec en el router.
5d20h: ISAKMP (0:0): received packet from 172.16.172.21 (N) NEW SA
5d20h: ISAKMP: local port 500, remote port 500
5d20h: ISAKMP (0:81): processing SA payload. message ID = 0
5d20h: ISAKMP (0:81): found peer pre-shared key matching 172.16.172.21
5d20h: ISAKMP (0:81): Checking ISAKMP transform 1 against priority 1 policy
5d20h: ISAKMP: encryption DES-CBC
5d20h: ISAKMP: hash SHA
5d20h: ISAKMP: auth pre-share
5d20h: ISAKMP: default group 1
5d20h: ISAKMP (0:81): atts are not acceptable. Next payload is 3
5d20h: ISAKMP (0:81): Checking ISAKMP transform 2 against priority 1 policy
5d20h: ISAKMP: encryption DES-CBC
5d20h: ISAKMP: hash MD5
5d20h: ISAKMP: auth pre-share
5d20h: ISAKMP: default group 2
5d20h: ISAKMP (0:81): atts are not acceptable. Next payload is 3
5d20h: ISAKMP (0:81): Checking ISAKMP transform 3 against priority 1 policy
5d20h: ISAKMP: encryption DES-CBC
5d20h: ISAKMP: hash MD5
5d20h: ISAKMP: auth pre-share
5d20h: ISAKMP: default group 1
5d20h: ISAKMP (0:81): atts are acceptable. Next payload is 0
5d20h: ISAKMP (0:81): processing vendor id payload
5d20h: ISAKMP (0:81): SA is doing pre-shared key authentication
using id type ID_IPV4_ADDR
5d20h: ISAKMP (0:81): sending packet to 172.16.172.21 (R) MM_SA_SETUP
5d20h: ISAKMP (0:81): received packet from 172.16.172.21 (R) MM_SA_SETUP
5d20h: ISAKMP (0:81): processing KE payload. message ID = 0
5d20h: ISAKMP (0:81): processing NONCE payload. message ID = 0
5d20h: ISAKMP (0:81): found peer pre-shared key matching 172.16.172.21
5d20h: ISAKMP (0:81): SKEYID state generated
5d20h: ISAKMP (0:81): sending packet to 172.16.172.21 (R) MM_KEY_EXCH
5d20h: ISAKMP (0:81): received packet from 172.16.172.21 (R) MM_KEY_EXCH
5d20h: ISAKMP (0:81): processing ID payload. message ID = 0
5d20h: ISAKMP (0:81): processing HASH payload. message ID = 0
5d20h: ISAKMP (0:81): SA has been authenticated with 172.16.172.21
5d20h: ISAKMP (81): ID payload
next-payload : 8
type : 1
protocol : 17
port : 500
length : 8
5d20h: ISAKMP (81): Total payload length: 12
5d20h: ISAKMP (0:81): sending packet to 172.16.172.21 (R) QM_IDLE
5d20h: ISAKMP (0:81): received packet from 172.16.172.21 (R) QM_IDLE
5d20h: ISAKMP (0:81): processing HASH payload. message ID = 241
5d20h: ISAKMP (0:81): processing SA payload. message ID = 241
5d20h: ISAKMP (0:81): Checking IPSec proposal 1
5d20h: ISAKMP: transform 1, ESP_DES
5d20h: ISAKMP: attributes in transform:
5d20h: ISAKMP: SA life type in seconds
5d20h: ISAKMP: SA life duration (VPI) of 0x0 0x0 0xD 0xAC
5d20h: ISAKMP: SA life type in kilobytes
5d20h: ISAKMP: SA life duration (VPI) of 0x0 0x10 0x0 0x0
5d20h: ISAKMP: encaps is 2
5d20h: ISAKMP: authenticator is HMAC-MD5
5d20h: ISAKMP (0:81): atts are acceptable.
5d20h: IPSEC(validate_proposal_request): proposal part #1,
(key eng. msg.) dest= 172.16.172.39, src= 172.16.172.21,
dest_proxy= 172.16.172.39/255.255.255.255/47/0 (type=1),
src_proxy= 172.16.172.21/255.255.255.255/47/0 (type=1),
protocol= ESP, transform= esp-des esp-md5-hmac ,
lifedur= 0s and 0kb,
spi= 0x0(0), conn_id= 0, keysize= 0, flags= 0x0
5d20h: ISAKMP (0:81): processing NONCE payload. message ID = 241
5d20h: ISAKMP (0:81): processing ID payload. message ID = 241
5d20h: ISAKMP (81): ID_IPV4_ADDR src 172.16.172.21 prot 47 port 0
5d20h: ISAKMP (0:81): processing ID payload. message ID = 241
5d20h: ISAKMP (81): ID_IPV4_ADDR dst 172.16.172.39 prot 47 port 0
5d20h: ISAKMP (0:81): asking for 1 spis from ipsec
5d20h: IPSEC(key_engine): got a queue event...
5d20h: IPSEC(spi_response): getting spi 895566248 for SA
from 172.16.172.21 to 172.16.172.39 for prot 3
5d20h: ISAKMP: received ke message (2/1)
5d20h: ISAKMP (0:81): sending packet to 172.16.172.21 (R) QM_IDLE
5d20h: ISAKMP (0:81): received packet from 172.16.172.21 (R) QM_IDLE
5d20h: ISAKMP (0:81): Creating IPSec SAs
5d20h: inbound SA from 172.16.172.21 to 172.16.172.39
(proxy 172.16.172.21 to 172.16.172.39)
5d20h: has spi 0x356141A8 and conn_id 362 and flags 0
5d20h: lifetime of 3500 seconds
5d20h: lifetime of 1048576 kilobytes
5d20h: outbound SA from 172.16.172.39 to 172.16.172.21
(proxy 172.16.172.39 to 172.16.172.21 )
5d20h: has spi 337 and conn_id 363 and flags 0
5d20h: lifetime of 3500 seconds
5d20h: lifetime of 1048576 kilobytes
5d20h: ISAKMP (0:81): deleting node 241 error FALSE reason
"quick mode done (await()"
5d20h: IPSEC(key_engine): got a queue event...
5d20h: IPSEC(initialize_sas): ,
(key eng. msg.) dest= 172.16.172.39, src= 172.16.172.21,
dest_proxy= 172.16.172.39/0.0.0.0/47/0 (type=1),
src_proxy= 172.16.172.21/0.0.0.0/47/0 (type=1),
protocol= ESP, transform= esp-des esp-md5-hmac ,
lifedur= 3500s and 1048576kb,
spi= 0x356141A8(895566248), conn_id= 362, keysize= 0, flags= 0x0
5d20h: IPSEC(initialize_sas): ,
(key eng. msg.) src= 172.16.172.39, dest= 172.16.172.21,
src_proxy= 172.16.172.39/0.0.0.0/47/0 (type=1),
dest_proxy= 172.16.172.21/0.0.0.0/47/0 (type=1),
protocol= ESP, transform= esp-des esp-md5-hmac ,
lifedur= 3500s and 1048576kb,
spi= 0x151(337), conn_id= 363, keysize= 0, flags= 0x0
5d20h: IPSEC(create_sa): sa created,
(sa) sa_dest= 172.16.172.39, sa_prot= 50,
sa_spi= 0x356141A8(895566248),
sa_trans= esp-des esp-md5-hmac , sa_conn_id= 362
5d20h: IPSEC(create_sa): sa created,
(sa) sa_dest= 172.16.172.21, sa_prot= 50,
sa_spi= 0x151(337),
sa_trans= esp-des esp-md5-hmac , sa_conn_id= 363
5d20h: IPSEC(add_sa): peer asks for new SAs -- expire current in 120 sec.,
(sa) sa_dest= 172.16.172.21, sa_prot= 50,
sa_spi= 0x150(336),
sa_trans= esp-des esp-md5-hmac , sa_conn_id= 361,
(identity) local= 172.16.172.39, remote= 172.16.172.21,
local_proxy= 172.16.172.39/255.255.255.255/47/0 (type=1),
remote_proxy= 172.16.172.21/255.255.255.255/47/0 (type=1)
1720-1#
1720-1#show crypto isakmp sa
dst src state conn-id slot
172.16.172.39 172.16.172.21 QM_IDLE 81 0
1720-1#show crypto ipsec sa
interface: FastEthernet0
Crypto map tag: vpn, local addr. 172.16.172.39
local ident (addr/mask/prot/port): (172.16.172.39/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (172.16.172.21/255.255.255.255/0/0)
current_peer: 172.16.172.21
PERMIT, flags={transport_parent,}
#pkts encaps: 0, #pkts encrypt: 0, #pkts digest 0
#pkts decaps: 0, #pkts decrypt: 0, #pkts verify 0
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0,
#pkts decompress failed: 0, #send errors 0, #recv errors 0
local crypto endpt.: 172.16.172.39, remote crypto endpt.: 172.16.172.21
path mtu 1514, media mtu 1514
current outbound spi: 0
inbound esp sas:
inbound ah sas:
inbound pcp sas:
outbound esp sas:
outbound ah sas:
outbound pcp sas:
local ident (addr/mask/prot/port): (172.16.172.39/255.255.255.255/47/0)
remote ident (addr/mask/prot/port): (172.16.172.21/255.255.255.255/47/0)
current_peer: 172.16.172.21
PERMIT, flags={origin_is_acl,transport_parent,parent_is_transport,}
#pkts encaps: 34901, #pkts encrypt: 34901, #pkts digest 34901
#pkts decaps: 34900, #pkts decrypt: 34900, #pkts verify 34900
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0,
#pkts decompress failed: 0, #send errors 0, #recv errors 0
local crypto endpt.: 172.16.172.39, remote crypto endpt.: 172.16.172.21
path mtu 1500, media mtu 1500
current outbound spi: 151
inbound esp sas:
spi: 0x356141A8(895566248)
transform: esp-des esp-md5-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 362, flow_id: 163, crypto map: vpn
sa timing: remaining key lifetime (k/sec): (1046258/3306)
IV size: 8 bytes
replay detection support: Y
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0x151(337)
transform: esp-des esp-md5-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 363, flow_id: 164, crypto map: vpn
sa timing: remaining key lifetime (k/sec): (1046258/3306)
IV size: 8 bytes
replay detection support: Y
outbound ah sas:
outbound pcp sas:
interface: Tunnel0
Crypto map tag: vpn, local addr. 172.16.172.39
local ident (addr/mask/prot/port): (172.16.172.39/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (172.16.172.21/255.255.255.255/0/0)
current_peer: 172.16.172.21
PERMIT, flags={transport_parent,}
#pkts encaps: 0, #pkts encrypt: 0, #pkts digest 0
#pkts decaps: 0, #pkts decrypt: 0, #pkts verify 0
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0,
#pkts decompress failed: 0, #send errors 0, #recv errors 0
local crypto endpt.: 172.16.172.39, remote crypto endpt.: 172.16.172.21
path mtu 1514, media mtu 1514
current outbound spi: 0
inbound esp sas:
inbound ah sas:
inbound pcp sas:
outbound esp sas:
outbound ah sas:
outbound pcp sas:
local ident (addr/mask/prot/port): (172.16.172.39/255.255.255.255/47/0)
remote ident (addr/mask/prot/port): (172.16.172.21/255.255.255.255/47/0)
current_peer: 172.16.172.21
PERMIT, flags={origin_is_acl,transport_parent,parent_is_transport,}
#pkts encaps: 35657, #pkts encrypt: 35657, #pkts digest 35657
#pkts decaps: 35656, #pkts decrypt: 35656, #pkts verify 35656
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts compr. failed: 0,
#pkts decompress failed: 0, #send errors 0, #recv errors 0
local crypto endpt.: 172.16.172.39, remote crypto endpt.: 172.16.172.21
path mtu 1500, media mtu 1500
current outbound spi: 151
inbound esp sas:
spi: 0x356141A8(895566248)
transform: esp-des esp-md5-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 362, flow_id: 163, crypto map: vpn
sa timing: remaining key lifetime (k/sec): (1046154/3302)
IV size: 8 bytes
replay detection support: Y
inbound ah sas:
inbound pcp sas:
outbound esp sas:
spi: 0x151(337)
transform: esp-des esp-md5-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 363, flow_id: 164, crypto map: vpn
sa timing: remaining key lifetime (k/sec): (1046154/3302)
IV size: 8 bytes
replay detection support: Y
outbound ah sas:
outbound pcp sas:
1720-1#show crypto engine connections active
ID Interface IP-Address State Algorithm Encrypt Decrypt
81 FastEthernet0 172.16.172.39 set HMAC_MD5+DES_56_CB 0 0
362 FastEthernet0 172.16.172.39 set HMAC_MD5+DES_56_CB 0 23194
363 FastEthernet0 172.16.172.39 set HMAC_MD5+DES_56_CB 23195 0
Depuraciones en el concentrador VPN 5002
Aquí se muestra la salida de Syslog en el concentrador VPN.
VPN5002_8_323E9040: Main# VPN 0:1 opened for 172.16.172.39 from 172.16.172.39.
User assigned IP address 50.1.1.2
VPN5002_8_323E9040: Main#show vpn partner verbose
Port Partner Partner Default Bindto Connect
Number Address Port Partner Address Time
--------------------------------------------------------------------------
VPN 0:1 172.16.172.39 500 No 172.16.172.21 00:00:13:26
Auth/Encrypt: MD5e/DES User Auth: Shared Key
Access: Static Peer: 172.16.172.39 Local: 172.16.172.21
Start:14518 seconds Managed:15299 seconds State:imnt_maintenance
IOP slot 1:
No active connections found.
VPN5002_8_323E9040: Main#show vpn statistics verbose
Current In High Running Script Script Script
Active Negot Water Total Starts OK Error
--------------------------------------------------------------
Users 0 0 0 0 0 0 0
Partners 1 0 1 81 81 1 158
Total 1 0 1 81 81 1 158
Stats VPN0:1
Wrapped 79733
Unwrapped 79734
BadEncap 0
BadAuth 0
BadEncrypt 0
rx IP 79749
rx IPX 0
rx Other 0
tx IP 79761
tx IPX 0
tx Other 0
IKE rekey 0
Input VPN pkts dropped due to no SA: 0
Input VPN pkts dropped due to no free queue entries: 0
IOP slot 1:
Current In High Running Script Script Script
Active Negot Water Total Starts OK Error
--------------------------------------------------------------
Users 0 0 0 0 0 0 0
Partners 0 0 0 0 0 0 0
Total 0 0 0 0 0 0 0
Stats
Wrapped
Unwrapped
BadEncap
BadAuth
BadEncrypt
rx IP
rx IPX
rx Other
tx IP
tx IPX
tx Other
IKE rekey
Input VPN pkts dropped due to no SA: 0
Input VPN pkts dropped due to no free queue entries: 0
Configuración incorrecta del modo de túnel
El concentrador VPN 5000 propone el modo de transporte de forma predeterminada cuando se utiliza GRE sobre IPSec. Cuando el router Cisco IOS está mal configurado para el modo de túnel, se producen estos errores.
Aquí se muestra la salida de depuración en el router Cisco IOS.
2d21h: ISAKMP (0:23): Checking IPSec proposal 1 2d21h: ISAKMP: transform 1, ESP_DES 2d21h: ISAKMP: attributes in transform: 2d21h: ISAKMP: SA life type in seconds 2d21h: ISAKMP: SA life duration (VPI) of 0x0 0x1 0x51 0x80 2d21h: ISAKMP: SA life type in kilobytes 2d21h: ISAKMP: SA life duration (VPI) of 0x0 0x10 0x0 0x0 2d21h: ISAKMP: encaps is 2 2d21h: ISAKMP: authenticator is HMAC-MD5 2d21h: IPSEC(validate_proposal): invalid transform proposal flags -- 0x0
El registro en el VPN 5002 Concentrator muestra una entrada similar a esta salida.
lan-lan-VPN0:1:[172.16.172.39]: received notify from partner -- notify: NO PROPOSAL CHOSEN
Información Relacionada
Historial de revisiones
| Revisión | Fecha de publicación | Comentarios |
|---|---|---|
1.0 |
05-Sep-2001 |
Versión inicial |
ComentariosContacte a Cisco
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