Configurazione di GRE over IPSec tra un router Cisco IOS e un concentratore VPN 5000 con RIP e CVC

Introduzione

In questa configurazione di esempio viene descritto come configurare GRE (Generic Routing Encapsulation) su IPSec tra un concentratore Cisco VPN 5000 e un router Cisco IOS®. La funzione GRE-over-IPSec è stata introdotta nel software VPN 5000 Concentrator 6.0(19).

In questo esempio, il protocollo RIP (Routing Information Protocol) viene utilizzato come protocollo di routing dinamico per instradare il traffico attraverso il tunnel VPN.

Prerequisiti

Requisiti

Nessun requisito specifico previsto per questo documento.

Componenti usati

Le informazioni fornite in questo documento si basano sulle seguenti versioni software e hardware:

• Software Cisco IOS release 12.1(5)T7

• Software VPN 5000 Concentrator release 6.0(19)

Le informazioni discusse in questo documento fanno riferimento a dispositivi usati in uno specifico ambiente di emulazione. Su tutti i dispositivi menzionati nel documento la configurazione è stata ripristinata ai valori predefiniti. Se la rete è operativa, valutare attentamente eventuali conseguenze derivanti dall'uso dei comandi.

Convenzioni

Per ulteriori informazioni sulle convenzioni usate, consultare il documento Cisco sulle convenzioni nei suggerimenti tecnici.

Configurazione

In questa sezione vengono presentate le informazioni necessarie per configurare le funzionalità descritte più avanti nel documento.

Nota: per ulteriori informazioni sui comandi menzionati in questo documento, usare lo strumento di ricerca dei comandi (solo utenti registrati).

Esempio di rete

Per la stesura di questo documento è stata utilizzata la configurazione di rete illustrata in questo diagramma.

Il protocollo GRE over IPSec è configurato tra il router Cisco IOS (7140) e Cisco VPN 5008 Concentrator. Dietro a questi dispositivi, più reti vengono pubblicizzate tramite RIP, che funziona all'interno del tunnel GRE tra 7140 e VPN 5008.

Le reti alla base di Cisco 7140 sono:

• 10.31.0.0/17

Le reti alla base di VPN 5008 sono:

• 172.18.124.0.0/24

• 20.20.20.0/24

• 10.0.0.0/24

Configurazioni

Nel documento vengono usate le configurazioni mostrate di seguito.

• Cisco IOS Router

• VPN 5000 Concentrator

• CVC

Building configuration...

Current configuration : 1607 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname 03-vpn-7140
!
boot system flash disk1:c7100-ik8s-mz.122-3
logging rate-limit console 10 except errors
enable password <removed>
!
ip subnet-zero
ip cef
!
!
no ip finger
!
! 
!--- Define phase 1 policy.

crypto isakmp policy 10
authentication pre-share

!--- Define the PreShared Key for the Remote peer !--- (5000 ) in this example.

crypto isakmp key cisco123 address 10.32.1.161
!

!--- Define Phase 2 policy. !--- Make sure that Transport Mode is enabled.

crypto ipsec transform-set www esp-des esp-sha-hmac 
mode transport
!

!--- Define the crypto map that is later !--- applied on the outbound interface.


crypto map temp 10 ipsec-isakmp 
set peer 10.32.1.161
set transform-set www 
match address 100
!
call rsvp-sync
!
!
!
!
!
!
!
controller ISA 5/1
!

!--- Define the GRE tunnel on the router. !--- Tunnel source is the outbound interface !--- and tunnel destination is VPN 5000.

interface Tunnel0
ip address 10.1.1.2 255.255.255.0
tunnel source FastEthernet0/0
tunnel destination 10.32.1.161
crypto map temp
!

!--- Outbound Interface that is connected to the Internet.

interface FastEthernet0/0
ip address 10.32.1.162 255.255.128.0
duplex auto
speed auto
crypto map temp
!
!
!--- Inside interface.

interface FastEthernet0/1
ip address 10.31.100.1 255.255.128.0
no keepalive
duplex auto
speed auto
!
interface Serial1/0
no ip address
shutdown
framing c-bit
cablelength 10
dsu bandwidth 44210
!
interface Serial1/1
no ip address
shutdown
framing c-bit
cablelength 10
dsu bandwidth 44210
!

!--- Define RIP Routing Protocol on the router. !--- This example shows Version 2 for classless routing.

router rip
version 2
network 10.0.0.0
no auto-summary
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.32.1.1
no ip http server
!

!--- Encryption access-list that is used !--- to encrypt the GRE packets.
 
access-list 100 permit gre host 10.32.1.162 host 10.32.1.161
!
!
line con 0
exec-timeout 0 0
transport input none
line aux 0
line vty 5 15
!
end

show configuration
Edited Configuration not Present, using Running
[ IP Ethernet 0:0 ]
SubnetMask = 255.255.255.0
IPAddress = 1.1.1.1

[ IP Ethernet 1:0 ]Mode = Routed
SubnetMask = 255.255.128.0
IPAddress = 10.32.1.161

[ General ]
VPNGateway = 10.32.1.1
EnablePassword = <removed>
Password = <removed>
EthernetAddress = 00:00:a5:e9:c8:00
DeviceType = VPN 5002/8 Concentrator
ConfiguredOn = Timeserver not configured
ConfiguredFrom = Command Line, from Console

[ IKE Policy ]
Protection = SHA_DES_G1

[ IP Static ]
0.0.0.0 0.0.0.0 10.32.1.1 1 redist=none

[ Context List ]
flash://rip.cfg

[ Logging ]
Enabled = On
Level = 7

Configuration size is 822 out of 65500 bytes.
VPN5002_8_A5E9C800: Main#

show configuration

Edited Configuration not Present, using Running

[ General ]
Context = "rip"

[ IP Ethernet 1:0.1 ]
VLANID = 124
Encapsulation = dot1q
Mode = Routed
SubnetMask = 255.255.255.0
IPAddress = 172.18.124.219

[ IP Static ]


[ Tunnel Partner VPN 1 ]
InactivityTimeout = 120
Transform = esp(sha,des)
KeyManage = ReliablePeer = "10.31.0.0/17"
LocalAccess = "10.5.1.0/24"
SharedKey = "cisco123"
Mode = Main
TunnelType = GREinIPSec
BindTo = "Ethernet 1:0"
Partner = 10.32.1.162

[ IP VPN 1 ]
RIPIn = On
RIPOut = On
RIPVersion = V2
DirectedBroadcast = Off
Numbered = On
Mode = Routed
SubnetMask = 255.255.255.0
IPAddress = 10.1.1.1

[ IP Ethernet 1:0.2 ]
Mode = Routed
SubnetMask = 255.255.255.0
IPAddress = 20.20.20.20

Configuration size is 1127 out of 65500 bytes.


VPN5002_8_A5E9C800: rip#

Verifica

Le informazioni contenute in questa sezione permettono di verificare che la configurazione funzioni correttamente.

Alcuni comandi show sono supportati dallo strumento Output Interpreter (solo utenti registrati); lo strumento permette di visualizzare un'analisi dell'output del comando show.

• show ip route: visualizza lo stato corrente della tabella di routing.

• show crypto engine connection active: visualizza il contatore di crittografia/decrittografia dei pacchetti per associazione di protezione IPSec.

• show crypto ipsec sa: visualizza tutte le associazioni di protezione IPSec correnti.

• show system log buffer: visualizza le informazioni di base sul syslog.

• vpn trace dump: visualizza informazioni dettagliate sui processi VPN.

03-vpn-7140#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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 10.32.1.1 to network 0.0.0.0

20.0.0.0/24 is subnetted, 1 subnets
R 20.20.20.0 [120/1] via 10.1.1.1, 00:00:10, Tunnel0
172.18.0.0/16 is variably subnetted, 2 subnets, 2 masks
R 172.18.124.0/24 [120/1] via 10.1.1.1, 00:00:10, Tunnel0
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
R 10.0.0.0/24 [120/2] via 10.1.1.1, 00:00:10, Tunnel0
C 10.1.1.0/24 is directly connected, Tunnel0
C 10.31.0.0/17 is directly connected, FastEthernet0/1
C 10.32.0.0/17 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 [1/0] via 10.32.1.1
03-vpn-7140#

03-vpn-7140#show crypto enggine connection active

ID Interface IP-Address State Algorithm Encrypt Decrypt
3 FastEthernet0/0 10.32.1.162 set HMAC_SHA+DES_56_CB 0 0
4 FastEthernet0/0 10.32.1.162 set HMAC_SHA+DES_56_CB 0 0
5 FastEthernet0/0 10.32.1.162 set HMAC_SHA+DES_56_CB 0 0
2098 FastEthernet0/0 10.32.1.162 set HMAC_SHA+DES_56_CB 0 1892
2099 FastEthernet0/0 10.32.1.162 set HMAC_SHA+DES_56_CB 11552 0

03-vpn-7140#show crypto ipsec sa

interface: FastEthernet0/0
Crypto map tag: temp, local addr. 10.32.1.162

local ident (addr/mask/prot/port): (10.32.1.162/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (10.32.1.161/255.255.255.255/0/0)
current_peer: 10.32.1.161
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.: 10.32.1.162, remote crypto endpt.: 10.32.1.161
path mtu 1500, media mtu 1500
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): (10.32.1.162/255.255.255.255/47/0)
remote ident (addr/mask/prot/port): (10.32.1.161/255.255.255.255/47/0)
current_peer: 10.32.1.161
PERMIT, flags={origin_is_acl,transport_parent,}
#pkts encaps: 12912, #pkts encrypt: 12912, #pkts digest 12912
#pkts decaps: 2382, #pkts decrypt: 2382, #pkts verify 2382
#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.: 10.32.1.162, remote crypto endpt.: 10.32.1.161
path mtu 1500, media mtu 1500
current outbound spi: 101

inbound esp sas:
spi: 0x4624F3AD(1176826797)
transform: esp-des esp-sha-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 2098, flow_id: 69, crypto map: temp



sa timing: remaining key lifetime (k/sec): (1048130/3179)
IV size: 8 bytes
replay detection support: Y

inbound ah sas:

inbound pcp sas:

outbound esp sas:
spi: 0x101(257)
transform: esp-des esp-sha-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 2099, flow_id: 70, crypto map: temp
sa timing: remaining key lifetime (k/sec): (1046566/3179)
IV size: 8 bytes
replay detection support: Y

outbound ah sas:

outbound pcp sas:



interface: Tunnel0
Crypto map tag: temp, local addr. 10.32.1.162

local ident (addr/mask/prot/port): (10.32.1.162/255.255.255.255/0/0)
remote ident (addr/mask/prot/port): (10.32.1.161/255.255.255.255/0/0)
current_peer: 10.32.1.161
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.: 10.32.1.162, remote crypto endpt.: 10.32.1.161
path mtu 1500, media mtu 1500
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): (10.32.1.162/255.255.255.255/47/0)
remote ident (addr/mask/prot/port): (10.32.1.161/255.255.255.255/47/0)
current_peer: 10.32.1.161
PERMIT, flags={origin_is_acl,transport_parent,}
#pkts encaps: 13017, #pkts encrypt: 13017, #pkts digest 13017
#pkts decaps: 2410, #pkts decrypt: 2410, #pkts verify 2410
#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.: 10.32.1.162, remote crypto endpt.: 10.32.1.161
path mtu 1500, media mtu 1500
current outbound spi: 101

inbound esp sas:
spi: 0x4624F3AD(1176826797)
transform: esp-des esp-sha-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 2098, flow_id: 69, crypto map: temp
sa timing: remaining key lifetime (k/sec): (1048124/3176)
IV size: 8 bytes
replay detection support: Y

inbound ah sas:

inbound pcp sas:

outbound esp sas:
spi: 0x101(257)
transform: esp-des esp-sha-hmac ,
in use settings ={Transport, }
slot: 0, conn id: 2099, flow_id: 70, crypto map: temp
sa timing: remaining key lifetime (k/sec): (1046566/3176)
IV size: 8 bytes
replay detection support: Y

outbound ah sas:

outbound pcp sas:

Risoluzione dei problemi

In questa sezione vengono fornite informazioni utili per risolvere i problemi di configurazione.

Comandi per la risoluzione dei problemi

Alcuni comandi show sono supportati dallo strumento Output Interpreter (solo utenti registrati); lo strumento permette di visualizzare un'analisi dell'output del comando show.

Nota: prima di usare i comandi di debug, consultare le informazioni importanti sui comandi di debug.

• debug crypto isakmp (Cisco IOS Router): visualizza informazioni dettagliate sulla negoziazione IKE (Internet Key Exchange) fase I (modalità principale).

• debug crypto ipsec (Cisco IOS Router): visualizza informazioni dettagliate sulla negoziazione IKE fase II (modalità rapida).

• debug crypto engine (Cisco IOS Router): esegue il debug del processo di crittografia/decrittografia dei pacchetti e di Diffie-Hellman (DH).

• debug ip rip (Cisco IOS Router): esegue il debug del protocollo di routing RIP.

Eseguire il comando show ip routing da VPN 5000 Concentrator.

VPN5002_8_A5E9C800: rip#show ip routing

IP Routing Table for rip
Directly Connected Routes:
Destination Mask Ref Uses Type Interface
10.1.1.0 FFFFFF00 5 STIF VPN0:1
10.1.1.0 FFFFFFFF 0 STIF Local
10.1.1.1 @FFFFFFFF 5 LocalLocal
10.1.1.255 FFFFFFFF 0 STIF Local
20.20.20.0 FFFFFF00 1352 STIF Ether1:0.2
20.20.20.0 FFFFFFFF 0 STIF Local
20.20.20.20 @FFFFFFFF 14 LocalLocal
20.20.20.255 FFFFFFFF 1318 STIF Local
127.0.0.1 FFFFFFFF 0 STIF Local
172.18.124.0 FFFFFF00 13789 STIF Ether1:0.1
172.18.124.0 FFFFFFFF 0 STIF Local
172.18.124.219 @FFFFFFFF 6 LocalLocal
172.18.124.255 FFFFFFFF 13547 STIF Local
224.0.0.5 FFFFFFFF 0 STIF Local
224.0.0.6 FFFFFFFF 0 STIF Local
224.0.0.9 FFFFFFFF 15 STIF Local
255.255.255.255 @FFFFFFFF 221 LocalLocal

Static Routes:
Destination Mask Gateway Metric Ref Uses Type Interface
10.31.0.0 FFFF0000 Interface 1 0 Stat VPN0:1
10.32.1.162 @FFFFFFFF 10.32.1.161 2 0 *Stat VPN0:1

Dynamic Routes:
Src/
Destination Mask Gateway Metric Ref Uses Type TTL Interface
DEFAULT 10.1.1.2 1 293 RIP2 165 VPN0:1
10.0.0.0 FFFFFF00 172.18.124.216 1 0 RIP1 160 Ether1:0.1
10.31.0.0 FFFF8000 10.1.1.2 1 0 RIP2 165 VPN0:1
10.32.0.0 FFFF8000 10.1.1.2 1 0 RIP2 165 VPN0:1

Configured IP Routes:
Destination Mask Gateway Metric IFnum Flags
10.31.0.0 FFFF0000 Interface 1 VPN 0:1 Redist = none 

Total Routes in use: 23 Mask -> @Host route Type -> Redist *rip #ospf

VPN5002_8_A5E9C800: rip#show vpn stat ver

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 1 1 0 0 
Total 1 0 1 1 1 0 0 

Stats VPN0:1
Wrapped 2697
Unwrapped 14439
BadEncap 0
BadAuth 0
BadEncrypt 0
rx IP 14439
rx IPX 0
rx Other 0
tx IP 2697
tx IPX 0
tx Other 0
IKE rekey 0

Input VPN pkts dropped due to no SA: 1

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

IOP slot 2:

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

IOP slot 3:

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

Informazioni correlate

• Pagina di supporto per Cisco VPN serie 5000 concentrator
• Pagina di supporto per i client Cisco VPN 5000
• Pagina di supporto per IPSec (IP Security Protocol)
• Supporto tecnico – Cisco Systems