ipsec vpn隐藏两边真实ip地址典型配置举例

分支与总部建立ipsec，因为安全要求，两边需要隐藏真实ip地址。地址对应关系如下：

192.168.1.2--------11.156.15.2

192.168.2.2--------188.1.102.2

总部配置

interface GigabitEthernet0/0

 port link-mode route

 combo enable copper

 ip address 172.168.1.1 255.255.255.0

 nat outbound 3002

 nat static enable

 ipsec apply policy 1

#

interface GigabitEthernet0/1

 port link-mode route

 combo enable copper

 ip address 192.168.1.1 255.255.255.0

#

 ip route-static 0.0.0.0 0 172.168.1.2

#

acl advanced 3000

 rule 0 permit ip source 11.156.15.0 0.0.0.255 destination 188.1.102.0 0.0.0.255

#

acl advanced 3001

 rule 0 permit ip source 192.168.1.0 0.0.0.255 destination 188.1.102.0 0.0.0.255

#

acl advanced 3002

 rule 0 deny ip source 11.156.15.0 0.0.0.255 destination 188.1.102.0 0.0.0.255

 rule 5 permit ip

#

ipsec transform-set 1

 esp encryption-algorithm 3des-cbc

 esp authentication-algorithm sha1

#

ipsec policy 1 1 isakmp

 transform-set 1

 security acl 3000

 local-address 172.168.1.1

 remote-address 172.168.2.1

 ike-profile 1

#

 nat static outbound 192.168.1.2 11.156.15.2 acl 3001 reversible

#

ike profile 1

 keychain 1

 local-identity address 172.168.1.1

 match remote identity address 172.168.2.1 255.255.255.255

 match local address 172.168.1.1

 proposal 1

#

ike proposal 1

 encryption-algorithm 3des-cbc

 authentication-algorithm md5

#

ike keychain 1

 pre-shared-key address 172.168.2.1 255.255.255.255 key cipher $c$3$q2ZNr6l8Ppj147aKkeLLNDOofxOajA==

#

分支配置

interface GigabitEthernet0/0

 port link-mode route

 combo enable copper

 ip address 172.168.2.1 255.255.255.0

 nat static enable

 ipsec apply policy 1

#

interface GigabitEthernet0/1

 port link-mode route

 combo enable copper

 ip address 192.168.2.1 255.255.255.0

#

 ip route-static 0.0.0.0 0 172.168.2.2

#

acl advanced 3000

 rule 0 permit ip source 188.1.102.0 0.0.0.255 destination 11.156.15.0 0.0.0.255

#

acl advanced 3001

 rule 0 permit ip source 192.168.2.0 0.0.0.255 destination 11.156.15.0 0.0.0.255

#

acl advanced 3002

 rule 0 deny ip source 188.1.102.0 0.0.0.255 destination 11.156.15.0 0.0.0.255

 rule 5 permit ip

#

ipsec transform-set 1

 esp encryption-algorithm 3des-cbc

 esp authentication-algorithm sha1

#

ipsec policy 1 1 isakmp

 transform-set 1

 security acl 3000

 local-address 172.168.2.1

 remote-address 172.168.1.1

 ike-profile 1

#

 nat static outbound 192.168.2.2 188.1.102.2 acl 3001 reversible

#

ike profile 1

 keychain 1

 local-identity address 172.168.2.1

 match remote identity address 172.168.1.1 255.255.255.255

 match local address 172.168.2.1

 proposal 1

#

ike proposal 1

 encryption-algorithm 3des-cbc

 authentication-algorithm md5

#

ike keychain 1

 pre-shared-key address 172.168.1.1 255.255.255.255 key cipher $c$3$MWlDyiWv5eklRKunSbCXO0OgTDSX6w==

#

验证配置

从分支内网ping 11.156.15.2

在分支查看ike sa及ipsec sa

[fenzhi]dis ike sa

    Connection-ID   Remote                Flag         DOI

------------------------------------------------------------------

    1               172.168.1.1           RD           IPsec

Flags:

RD--READY RL--REPLACED FD-FADING RK-REKEY

[fenzhi]dis ipse s

[fenzhi]dis ipse sa

-------------------------------

Interface: GigabitEthernet0/0

-------------------------------

 

  -----------------------------

  IPsec policy: 1

  Sequence number: 1

  Mode: ISAKMP

  -----------------------------

    Tunnel id: 0

    Encapsulation mode: tunnel

    Perfect Forward Secrecy:

    Inside VPN:

    Extended Sequence Numbers enable: N

    Traffic Flow Confidentiality enable: N

    Path MTU: 1444

    Tunnel:

        local  address: 172.168.2.1

        remote address: 172.168.1.1

    Flow:

        sour addr: 188.1.102.0/255.255.255.0  port: 0  protocol: ip

        dest addr: 11.156.15.0/255.255.255.0  port: 0  protocol: ip

 

    [Inbound ESP SAs]

      SPI: 3984720542 (0xed82029e)

      Connection ID: 4294967296

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-SHA1

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843197/1785

      Max received sequence-number: 24

      Anti-replay check enable: Y

      Anti-replay window size: 64

      UDP encapsulation used for NAT traversal: N

      Status: Active

 

    [Outbound ESP SAs]

      SPI: 3385141009 (0xc9c52711)

      Connection ID: 4294967297

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-SHA1

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843197/1785

      Max sent sequence-number: 24

      UDP encapsulation used for NAT traversal: N

      Status: Active

在分支查看nat 会话

[fenzhi]dis nat session verbose

Slot 0:

Initiator:

  Source      IP/port: 192.168.2.2/206

  Destination IP/port: 11.156.15.2/2048

  DS-Lite tunnel peer: -

  VPN instance/VLAN ID/VLL ID: -/-/-

  Protocol: ICMP(1)

  Inbound interface: GigabitEthernet0/1

Responder:

  Source      IP/port: 11.156.15.2/206

  Destination IP/port: 188.1.102.2/0

  DS-Lite tunnel peer: -

  VPN instance/VLAN ID/VLL ID: -/-/-

  Protocol: ICMP(1)

  Inbound interface: GigabitEthernet0/0

State: ICMP_REPLY

Application: OTHER

Start time: 2022-05-31 23:38:59  TTL: 25s

Initiator->Responder:            5 packets        420 bytes

Responder->Initiator:            5 packets        420 bytes

 

Total sessions found: 1

在总部查看ike sa及ipsec sa

<zongbu>dis ike sa

    Connection-ID   Remote                Flag         DOI

------------------------------------------------------------------

    1               172.168.2.1           RD           IPsec

Flags:

RD--READY RL--REPLACED FD-FADING RK-REKEY

<zongbu>dis ipse

<zongbu>dis ipsec sa

-------------------------------

Interface: GigabitEthernet0/0

-------------------------------

 

  -----------------------------

  IPsec policy: 1

  Sequence number: 1

  Mode: ISAKMP

  -----------------------------

    Tunnel id: 0

    Encapsulation mode: tunnel

    Perfect Forward Secrecy:

    Inside VPN:

    Extended Sequence Numbers enable: N

    Traffic Flow Confidentiality enable: N

    Path MTU: 1444

    Tunnel:

        local  address: 172.168.1.1

        remote address: 172.168.2.1

    Flow:

        sour addr: 11.156.15.0/255.255.255.0  port: 0  protocol: ip

        dest addr: 188.1.102.0/255.255.255.0  port: 0  protocol: ip

 

    [Inbound ESP SAs]

      SPI: 3385141009 (0xc9c52711)

      Connection ID: 4294967296

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-SHA1

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843197/1617

      Max received sequence-number: 29

      Anti-replay check enable: Y

      Anti-replay window size: 64

      UDP encapsulation used for NAT traversal: N

      Status: Active

 

    [Outbound ESP SAs]

      SPI: 3984720542 (0xed82029e)

      Connection ID: 4294967297

      Transform set: ESP-ENCRYPT-3DES-CBC ESP-AUTH-SHA1

      SA duration (kilobytes/sec): 1843200/3600

      SA remaining duration (kilobytes/sec): 1843197/1617

      Max sent sequence-number: 29

      UDP encapsulation used for NAT traversal: N

      Status: Active

 

在总部查看会话

[zongbu]dis nat session verbose

Slot 0:

Initiator:

  Source      IP/port: 188.1.102.2/207

  Destination IP/port: 11.156.15.2/2048

  DS-Lite tunnel peer: -

  VPN instance/VLAN ID/VLL ID: -/-/-

  Protocol: ICMP(1)

  Inbound interface: GigabitEthernet0/0

Responder:

  Source      IP/port: 192.168.1.2/207

  Destination IP/port: 188.1.102.2/0

  DS-Lite tunnel peer: -

  VPN instance/VLAN ID/VLL ID: -/-/-

  Protocol: ICMP(1)

  Inbound interface: GigabitEthernet0/1

State: ICMP_REPLY

Application: OTHER

Start time: 2022-05-31 23:40:50  TTL: 27s

Initiator->Responder:            5 packets        420 bytes

Responder->Initiator:            5 packets        420 bytes

 

Total sessions found: 1

1、 流量进入路由器要做源地址转换，到达对端之后要做目的地址转换所以要用静态地址转换。因为要双向互访所以要加reversible参数。

nat static outbound 192.168.2.2 188.1.102.2 acl 3001 reversible

2、 因为用户还要上公网所以要在静态nat中加入acl限制只有访问对端的流量才进行静态nat的转换。

3、 流量从设备转发出去时处理顺序是先nat再进行ipsec，所以可以在公网完成源地址转换及ipsec封装。流量进入则处理顺序相反。