Este documento describe los pasos que hay que seguir para traducir (NAT) el tráfico VPN que viaja sobre un túnel IPsec de LAN a LAN (L2L) entre dos dispositivos de seguridad y también PAT el tráfico de Internet. Cada dispositivo de seguridad tiene una red privada protegida detrás de ella. En este ejemplo, se conectan dos dispositivos de seguridad adaptable (ASA) de Cisco con redes internas idénticas y superpuestas a través del túnel VPN. En un escenario normal, la comunicación a través de la VPN nunca ocurre porque los paquetes ping nunca salen de la subred local ya que el usuario hace ping a la dirección IP de la misma subred. Para que estas dos redes internas privadas se comuniquen entre sí, la política NAT se utiliza en ambos ASA para la traducción de la subred local de modo que la comunicación se realice según lo esperado.
Asegúrese de haber configurado el dispositivo de seguridad adaptable de Cisco con direcciones IP en las interfaces y de tener conectividad básica antes de continuar con este ejemplo de configuración.
La información de este documento se basa en esta versión del software:
Cisco Adaptive Security Appliance Software Version 7.x y posterior.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Esta configuración también se puede usar con Cisco PIX Security Appliance Version 7.x y posterior.
Consulte Convenciones de Consejos Técnicos de Cisco para obtener más información sobre las convenciones sobre documentos.
En esta sección encontrará la información para configurar las funciones descritas en este documento.
Nota: Use el Command Lookup Tool (únicamente clientes registrados) para obtener más información sobre los comandos que se utilizan en esta sección.
En este documento, se utiliza esta configuración de red:
En este documento, se utilizan estas configuraciones:
ASA-1 |
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ASA-1#show running-config : Saved : ASA Version 8.0(3) ! hostname ciscoasa enable password 8Ry2YjIyt7RRXU24 encrypted names ! interface Ethernet0 nameif outside security-level 0 ip address 172.162.1.1 255.255.255.0 !--- Configure the outside interface. ! interface Ethernet1 nameif inside security-level 100 ip address 192.168.1.1 255.255.255.0 !--- Configure the inside interface. passwd 2KFQnbNIdI.2KYOU encrypted ftp mode passive access-list new extended permit ip 192.168.2.0 255.255.255.0 192.168.3.0 255.255.255.0 !--- This access list (new) is used with the crypto map (outside_map) !--- in order to determine which traffic should be encrypted !--- and sent across the tunnel. access-list policy-nat extended permit ip 192.168.1.0 255.255.255.0 192.168.3.0 255.255.255.0 !--- The policy-nat ACL is used with the static !--- command in order to match the VPN traffic for translation. pager lines 24 mtu outside 1500 mtu inside 1500 no failover asdm image flash:/asdm-615.bin no asdm history enable arp timeout 14400 static (inside,outside) 192.168.2.0 access-list policy-nat !--- It is a Policy NAT statement. !--- The static command with the access list (policy-nat), !--- which matches the VPN traffic and translates the source (192.168.1.0) to !--- 192.168.2.0 for outbound VPN traffic. global (outside) 1 interface nat (inside) 1 0.0.0.0 0.0.0.0 0 0 !--- The previous statements PAT the Internet traffic !--- except for the VPN traffic that uses the IP address 172.17.1.1. route outside 0.0.0.0 0.0.0.0 172.162.1.2 1 !--- Output is suppressed. !--- PHASE 2 CONFIGURATION ---! !--- The encryption types for Phase 2 are defined here. crypto ipsec transform-set CISCO esp-des esp-md5-hmac !--- Define the transform set for Phase 2. crypto map outside_map 20 match address new !--- Define which traffic should be sent to the IPsec peer with the !--- access list (new). crypto map outside_map 20 set peer 172.162.1.2 !--- Sets the IPsec peer (remote end point) crypto map outside_map 20 set transform-set CISCO !--- Sets the IPsec transform set "CISCO" !--- to be used with the crypto map entry "outside_map" crypto map outside_map interface outside !--- Specifies the interface to be used with !--- the settings defined in this configuration !--- PHASE 1 CONFIGURATION ---! !--- This configuration uses isakmp policy 65535. !--- Policy 65535 is included in the configuration by default. !--- These configuration commands define the !--- Phase 1 policy parameters that are used. crypto isakmp identity address crypto isakmp enable outside crypto isakmp policy 65535 authentication pre-share encryption des hash md5 group 2 lifetime 86400 tunnel-group 172.162.1.2 type ipsec-l2l !--- In order to create and manage the database of connection-specific records !--- for IPsec-L2L—IPsec (LAN-to-LAN) tunnels, use the tunnel-group !--- command in global configuration mode. !--- For L2L connections, the name of the tunnel group must be !--- the IP address of the IPsec peer (remote peer end). tunnel-group 172.162.1.2 ipsec-attributes pre-shared-key * !--- Enter the pre-shared key in order to configure the authentication method. telnet timeout 5 ssh timeout 5 console timeout 0 ! class-map inspection_default match default-inspection-traffic ! ! policy-map global_policy class inspection_default inspect dns maximum-length 512 inspect ftp inspect h323 h225 inspect h323 ras inspect netbios inspect rsh inspect rtsp inspect skinny inspect esmtp inspect sqlnet inspect sunrpc inspect tftp inspect sip inspect xdmcp ! service-policy global_policy global Cryptochecksum:33e1e37cd1280d908210dac0cc26e706 : end |
ASA-2 |
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ASA-2#show running-config : Saved : ASA Version 8.0(3) ! hostname ASA-2 enable password 8Ry2YjIyt7RRXU24 encrypted names ! interface Ethernet0 nameif outside security-level 0 ip address 172.162.1.2 255.255.255.0 ! interface Ethernet1 nameif inside security-level 100 ip address 192.168.1.1 255.255.255.0 ! !--- Output is suppressed. access-list new extended permit ip 192.168.3.0 255.255.255.0 192.168.2.0 255.255.255.0 !--- This access list (new) is used with the crypto map (outside_map) !--- in order to determine which traffic needs to be encrypted !--- and sent across the tunnel. access-list policy-nat extended permit ip 192.168.1.0 255.255.255.0 192.168.2.0 255.255.255.0 !--- The policy-nat ACL is used with the static !--- command in order to match the VPN traffic for translation. pager lines 24 mtu outside 1500 mtu inside 1500 no failover asdm image flash:/asdm-615.bin no asdm history enable arp timeout 14400 static (inside,outside) 192.168.3.0 access-list policy-nat !--- This is a Policy NAT statement. !--- The static command with the access list (policy-nat), !--- which matches the VPN traffic and translates the source (192.168.1.0) to !--- 192.168.3.0 for outbound VPN traffic. global (outside) 1 interface nat (inside) 1 0.0.0.0 0.0.0.0 0 0 !--- The previous statements PAT the Internet traffic !--- except the VPN traffic that uses the outside interface IP address. route outside 0.0.0.0 0.0.0.0 172.162.1.2 1 !--- PHASE 2 CONFIGURATION ---! !--- The encryption types for Phase 2 are defined here. crypto ipsec transform-set CISCO esp-des esp-md5-hmac !--- Define the transform set for Phase 2. crypto map outside_map 20 match address new !--- Define which traffic needs to be sent to the IPsec peer. crypto map outside_map 20 set peer 172.162.1.1 !--- Sets the IPsec peer. crypto map outside_map 20 set transform-set CISCO !--- Sets the IPsec transform set "CISCO" !--- to be used with the crypto map entry "outside_map". crypto map outside_map interface outside !--- Specifies the interface to be used with !--- the settings defined in this configuration. !--- PHASE 1 CONFIGURATION ---! !--- This configuration uses isakmp policy 65535 !--- which is included in the configuration by default. !--- The configuration commands here define the !--- Phase 1 policy parameters that are used. crypto isakmp identity address crypto isakmp enable outside crypto isakmp policy 65535 authentication pre-share encryption des hash md5 group 2 lifetime 86400 !--- Output is suppressed. !--- In order to create and manage the database of connection-specific !--- records for IPsec-L2L—IPsec (LAN-to-LAN) tunnels, use the !--- tunnel-group command in global configuration mode. !--- For L2L connections, the name of the tunnel group must be !--- the IP address of the IPsec peer. tunnel-group 172.162.1.1 type ipsec-l2l tunnel-group 172.162.1.1 ipsec-attributes pre-shared-key * !--- Enter the pre-shared key in order to configure the authentication method. prompt hostname context Cryptochecksum:6b505b4a05c1aee96a71e67c23e71865 : end |
Utilize esta sección para confirmar que su configuración funcione correctamente.
La herramienta Output Interpreter Tool (clientes registrados solamente) (OIT) soporta ciertos comandos show. Utilize el OIT para ver una análisis de la salida del comando show:
show crypto isakmp sa: muestra todas las asociaciones actuales de seguridad IKE (SA) de un par.
show crypto ipsec sa - Muestra la configuración utilizada por las SA actuales.
ASA-1#show crypto isakmp sa Active SA: 1 Rekey SA: 0 (A tunnel will report 1 Active and 1 Rekey SA during rekey) Total IKE SA: 1 1 IKE Peer: 172.162.1.2 Type : L2L Role : initiator Rekey : no State : MM_ACTIVE
ASA-1#show crypto ipsec sa interface: outside Crypto map tag: outside_map, seq num: 20, local addr: 172.162.1.1 access-list new permit ip 192.168.2.0 255.255.255.0 192.168.3.0 255.255.2 5.0 local ident (addr/mask/prot/port): (192.168.2.0/255.255.255.0/0/0) remote ident (addr/mask/prot/port): (192.168.3.0/255.255.255.0/0/0) current_peer: 172.162.1.2 #pkts encaps: 9, #pkts encrypt: 9, #pkts digest: 9 #pkts decaps: 9, #pkts decrypt: 9, #pkts verify: 9 #pkts compressed: 0, #pkts decompressed: 0 #pkts not compressed: 9, #pkts comp failed: 0, #pkts decomp failed: 0 #pre-frag successes: 0, #pre-frag failures: 0, #fragments created: 0 #PMTUs sent: 0, #PMTUs rcvd: 0, #decapsulated frgs needing reassembly: 0 #send errors: 0, #recv errors: 0 local crypto endpt.: 172.162.1.1, remote crypto endpt.: 172.162.1.2 path mtu 1500, ipsec overhead 58, media mtu 1500 current outbound spi: 0BA6CD7E inbound esp sas: spi: 0xFB4BD01A (4216049690) transform: esp-des esp-md5-hmac none in use settings ={L2L, Tunnel, } slot: 0, conn_id: 8192, crypto-map: outside_map sa timing: remaining key lifetime (kB/sec): (3824999/27738) IV size: 8 bytes replay detection support: Y outbound esp sas: spi: 0x0BA6CD7E (195480958) transform: esp-des esp-md5-hmac none in use settings ={L2L, Tunnel, } slot: 0, conn_id: 8192, crypto-map: outside_map sa timing: remaining key lifetime (kB/sec): (3824999/27738) IV size: 8 bytes replay detection support: Y
ASA-1#show nat NAT policies on Interface inside: match ip inside 192.168.1.0 255.255.255.0 outside 192.168.3.0 255.255.255.0 static translation to 192.168.2.0 translate_hits = 12, untranslate_hits = 5 match ip inside any outside any dynamic translation to pool 1 (172.162.1.1 [Interface PAT]) translate_hits = 0, untranslate_hits = 0 match ip inside any inside any dynamic translation to pool 1 (No matching global) translate_hits = 0, untranslate_hits = 0 match ip inside any dmz any dynamic translation to pool 1 (No matching global) translate_hits = 0, untranslate_hits = 0
ASA-1#show xlate 1 in use, 1 most used Global 192.168.2.0 Local 192.168.1.0
ASA-2#show crypto ipsec sa interface: outside Crypto map tag: outside_map, seq num: 20, local addr: 172.162.1.2 access-list new permit ip 192.168.3.0 255.255.255.0 192.168.2.0 255.255.25 5.0 local ident (addr/mask/prot/port): (192.168.3.0/255.255.255.0/0/0) remote ident (addr/mask/prot/port): (192.168.2.0/255.255.255.0/0/0) current_peer: 172.162.1.1 #pkts encaps: 9, #pkts encrypt: 9, #pkts digest: 9 #pkts decaps: 9, #pkts decrypt: 9, #pkts verify: 9 #pkts compressed: 0, #pkts decompressed: 0 #pkts not compressed: 9, #pkts comp failed: 0, #pkts decomp failed: 0 #pre-frag successes: 0, #pre-frag failures: 0, #fragments created: 0 #PMTUs sent: 0, #PMTUs rcvd: 0, #decapsulated frgs needing reassembly: 0 #send errors: 0, #recv errors: 0 local crypto endpt.: 172.162.1.2, remote crypto endpt.: 172.162.1.1 path mtu 1500, ipsec overhead 58, media mtu 1500 current outbound spi: FB4BD01A inbound esp sas: spi: 0x0BA6CD7E (195480958) transform: esp-des esp-md5-hmac none in use settings ={L2L, Tunnel, } slot: 0, conn_id: 8192, crypto-map: outside_map sa timing: remaining key lifetime (kB/sec): (4274999/26902) IV size: 8 bytes replay detection support: Y outbound esp sas: spi: 0xFB4BD01A (4216049690) transform: esp-des esp-md5-hmac none in use settings ={L2L, Tunnel, } slot: 0, conn_id: 8192, crypto-map: outside_map sa timing: remaining key lifetime (kB/sec): (4274999/26902) IV size: 8 bytes replay detection support: Y
ASA-2#show crypto isakmp sa Active SA: 1 Rekey SA: 0 (A tunnel will report 1 Active and 1 Rekey SA during rekey) Total IKE SA: 1 1 IKE Peer: 172.162.1.1 Type : L2L Role : responder Rekey : no State : MM_ACTIVE
Cuando resuelva problemas, asegúrese de borrar las SA existentes después de realizar un cambio. En el modo privilegiado del PIX, use estos comandos:
clear crypto ipsec sa - Elimina las SAs IPsec activas.
clear crypto isakmp sa - Elimina las SA IKE activas.
La herramienta de interpretación de información de salida (disponible para clientes registrados únicamente) admite ciertos comandos show. Utilize el OIT para ver una análisis de la salida del comando show.
Nota: Consulte Información Importante sobre Comandos Debug antes de utilizar los comandos debug.
debug crypto ipsec - Muestra los IPSec Negotiations de la Fase 2.
debug crypto isakmp - Muestra las negociaciones ISAKMP para la fase 1.
Revisión | Fecha de publicación | Comentarios |
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1.0 |
09-Dec-2010 |
Versión inicial |