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配置带有NAT的PIX实现IPSec VPN连接

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在此示例配置，远程PIX 通过动态主机配置协议(DHCP)收到IP地址并且连接到中央PIX。此配置允许中央PIX接受动态IPSec连接。

作者：中国IT实验室来源：中国IT实验室 2009年2月2日

关键字： VPN PIX NAT

　　前言

　　在此示例配置，远程PIX 通过动态主机配置协议(DHCP)收到IP地址并且连接到中央PIX。此配置允许中央PIX接受动态IPSec连接。远程PIX使用网络地址转换(NAT) "加入"专用地址设备在它之后对专用地址网络在中央PIX 之后。远程PIX可以首次与中央PIX (的连接知道终端)，但中央PIX不可以首次与远程PIX (的连接不知道终端)。

　　在此示例配置，Tiger是远程PIX和 Lion 是中央PIX。我们不了解什么Tiger的IP地址将是，因此我们必须配置Lion动态地接受连接从任何地方知道计算机通配符，预共享密钥。 Tiger知道什么数据流将被加密(因为由访问控制列表指定)并且Lion终点哪里被找出。 Tiger必须首次连接。两边执行NAT和NAT 0 绕过NAT为IPSec信息数据流。

　　另外，异地用户在此配置连接到中央 PIX (Lion)使用异地用户不能连接到远程PIX的 Cisco VPN Client 3.x. (Tiger)因为两边将有并且不知道在哪里发送请求的动态地指定的IP地址。

　　在您开始之前

　　惯例

　　欲知关于文件惯例的更多信息，请参阅 Cisco技术提示惯例。

　　前提

　　此文档没有特殊的先决条件。

　　使用的组件

　　此配置使用以下的软件及硬件版本实施了并且测试了。

　　Cisco PIX防火墙软件版本6.0(1) (或极大为 Cisco VPN Client 3.x)

　　Cisco PIX防火墙软件版本5.3.1 (远程PIX)

　　Cisco VPN客户端版本3.x

　　配置

　　在此部分，您介绍用信息配置在本文描述的功能。

　　注意：找到其它信息关于用于本文的命令，使用IOS命令查找工具。

　　网络图

　　本文使用网络建立图示如下的。

　　Lion配置


Building configuration...
: Saved
:
PIX Version 6.0(1)
nameif gb-ethernet0 spare1 security10
nameif gb-ethernet1 spare2 security15
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname lion
domain-name cisco.com
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060
fixup protocol skinny 2000
names
!

!--- ACL to avoid Network Address Translation (NAT) on the IPSec packets

access-list 100 permit ip 10.2.2.0 255.255.255.0 10.1.1.0 255.255.255.0 
access-list 100 permit ip 10.2.2.0 255.255.255.0 10.3.3.0 255.255.255.0
!
pager lines 24
logging buffered debugging
interface gb-ethernet0 1000auto shutdown
interface gb-ethernet1 1000auto shutdown
interface ethernet0 10baset
interface ethernet1 10baset
mtu spare1 1500
mtu spare2 1500
mtu outside 1500
mtu inside 1500
ip address spare1 127.0.0.1 255.255.255.255
ip address spare2 127.0.0.1 255.255.255.255
!

!--- IP addresses on the interfaces

ip address outside 203.1.1.1 255.255.255.0
ip address inside 10.2.2.1 255.255.255.0
!
ip audit info action alarm
ip audit attack action alarm
ip local pool clientpool 10.3.3.1-10.3.3.10
no failover
failover timeout 0:00:00
failover poll 15
failover ip address spare1 0.0.0.0
failover ip address spare2 0.0.0.0
failover ip address outside 0.0.0.0
failover ip address inside 0.0.0.0
pdm history enable
arp timeout 14400

!--- global (outside) 1 203.1.1.10-203.1.1.15
!--- Change from NAT to PAT on DHCP interface

global (outside) 1 interface
!

!--- Binding ACL 100 to the NAT statement to avoid NAT on the IPSec packets

nat (inside) 0 access-list 100
!
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
conduit permit icmp any any
!

!--- Default route to the Internet

route outside 0.0.0.0 0.0.0.0 203.1.1.2 1
!
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 0:05:00 sip 
0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
!

!--- The sysopt command avoids conduit on the IPSec encrypted traffic

sysopt connection permit-ipsec
!
no sysopt route dnat
!

!--- Phase 2 encryption type

crypto ipsec transform-set myset esp-des esp-md5-hmac
crypto dynamic-map cisco 1 set transform-set myset
crypto map dyn-map 20 ipsec-isakmp dynamic cisco
!

!--- Binding the IPSec engine on the outside interface

crypto map dyn-map interface outside
!

!--- Enabling ISAKMP key-exchange

isakmp enable outside
!

!--- ISAKMP Policy for accepting dynamic connections from remote PIX

isakmp key ******** address 0.0.0.0 netmask 0.0.0.0

!--- ISAKMP Policy for Cisco VPN Client 2.x

isakmp policy 10 authentication pre-share
isakmp policy 10 encryption des
isakmp policy 10 hash md5
isakmp policy 10 group 1
isakmp policy 10 lifetime 1000
!

!--- ISAKMP Policy for Cisco VPN Client 3.x

isakmp policy 20 authentication pre-share
isakmp policy 20 encryption des
isakmp policy 20 hash sha
isakmp policy 20 group 2
isakmp policy 20 lifetime 86400
!

!--- IPSec group configuration for either client

vpngroup unityclient address-pool clientpool
vpngroup unityclient dns-server 10.1.1.3
vpngroup unityclient wins-server 10.1.1.3
vpngroup unityclient default-domain cisco.com
vpngroup unityclient idle-time 1800
vpngroup unityclient password ********
!
telnet timeout 5
ssh timeout 5
terminal width 80
Cryptochecksum:d6fe92db883a052c5765be21a74e7c8d
: end
[OK]

　　Tiger配置


Building configuration...
: Saved
:
PIX Version 5.3(1)
nameif gb-ethernet0 spare1 security10
nameif gb-ethernet1 spare2 security15
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname tiger
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060
names
!

!--- ACL to avoid Network Address Translation (NAT) on the IPSec packets

access-list 101 permit ip 10.1.1.0 255.255.255.0 10.2.2.0 255.255.255.0
!
pager lines 24
logging on
no logging timestamp
no logging standby
no logging console
no logging monitor
logging buffered debugging
no logging trap
no logging history
logging facility 20
logging queue 512
interface gb-ethernet0 1000auto shutdown
interface gb-ethernet1 1000auto shutdown
interface ethernet0 10baset
interface ethernet1 10baset
mtu spare1 1500
mtu spare2 1500
mtu outside 1500
mtu inside 1500
ip address spare1 127.0.0.1 255.255.255.255
ip address spare2 127.0.0.1 255.255.255.255
!
ip address outside dhcp
ip address inside 10.1.1.1 255.255.255.0
!
ip audit info action alarm
ip audit attack action alarm
no failover
failover timeout 0:00:00
failover poll 15
failover ip address spare1 0.0.0.0
failover ip address spare2 0.0.0.0
failover ip address outside 0.0.0.0
failover ip address inside 0.0.0.0
arp timeout 14400
global (outside) 1 204.1.1.10-204.1.1.15
!

!--- Binding ACL 101 to the NAT statement to avoid NAT on the IPSec packets

nat (inside) 0 access-list 101
!
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
conduit permit icmp any any
route outside 0.0.0.0 0.0.0.0 204.1.1.2 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 0:05:00 sip 
0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
!

!--- The sysopt command avoids conduit on the IPSec encrypted traffic

sysopt connection permit-ipsec
!
no sysopt route dnat
!

!--- Phase 2 encryption type

crypto ipsec transform-set myset esp-des esp-md5-hmac
crypto map newmap 10 ipsec-isakmp
crypto map newmap 10 match address 101
crypto map newmap 10 set peer 203.1.1.1
crypto map newmap 10 set transform-set myset
!

!--- Binding the IPSec engine on the outside interface

crypto map newmap interface outside
!

!--- Enabling ISAKMP key-exchange

isakmp enable outside
!

!--- ISAKMP Policy for connecting to Central PIX

isakmp key ******** address 203.1.1.1 netmask 255.255.255.255
isakmp identity hostname
isakmp policy 10 authentication pre-share
isakmp policy 10 encryption des
isakmp policy 10 hash md5
isakmp policy 10 group 1
isakmp policy 10 lifetime 1000
!
telnet timeout 5
ssh timeout 5
terminal width 80
Cryptochecksum:6743b7bf9476590ecd1a1a8c6d75245b
: end

　　验证

　　此部分提供您能使用确认您的配置适当地工作的信息。

　　注意：在配置模式必须执行clear命令。

　　clear crypto ipsec sa - 在失败的尝试以后重置IPSec协会协商VPN建立隧道。

　　clear crypto isakmp sa - 在失败的尝试以后重置互联网安全协会和密钥管理协议 (ISAKMP)安全关联协商VPN建立隧道。

　　show crypto engine ipsec - 显示加密的会话。

　　排除故障

　　此部分提供您能使用排除您的配置故障的信息。

　　故障检修命令

　　在尝试任何 debug 命令之前，请参阅重要信息关于Debug命令。

　　debug crypto ipsec - 看见客户端是否协商VPN连接的IPSec部分。

　　debug crypto isakmp connection - 看见对等体是否协商VPN的ISAKMP 部分

　　示例“Good ”调试输出中央PIX 调试远程PIX调试客户端调试中央PIX调试


中央PIX 调试 
远程PIX调试 
客户端调试 
中央PIX调试 
crypto_isakmp_process_block: src 204.1.1.1, dest 203.1.1.1
OAK_MM exchange
ISAKMP (0): processing SA payload. message ID = 0
ISAKMP (0): Checking ISAKMP transform 1 against priority 10 policy
ISAKMP:      encryption DES-CBC
ISAKMP:      hash MD5
ISAKMP:      default group 1
ISAKMP:      auth pre-share
ISAKMP:      life type in seconds
ISAKMP:      life duration (basic) of 1000
ISAKMP (0): atts are acceptable. Next payload is 0
ISAKMP (0): SA is doing pre-shared key authentication using id type ID_FQDN
return status is IKMP_NO_ERROR
crypto_isakmp_process_block: src 204.1.1.1, dest 203.1.1.1
OAK_MM exchange
ISAKMP (0): processing KE payload. message ID = 0
ISAKMP (0): processing NONCE payload. message ID = 0
ISAKMP (0): processing vendor id payload
ISAKMP (0): processing vendor id payload
ISAKMP (0): processing vendor id payload
ISAKMP (0): speaking to another IOS box!
return status is IKMP_NO_ERROR
crypto_isakmp_process_block: src 204.1.1.1, dest 203.1.1.1
OAK_MM exchange
ISAKMP (0): processing ID payload. message ID = 0
ISAKMP (0): processing HASH payload. message ID = 0
ISAKMP (0): SA has been authenticated
ISAKMP (0): ID payload
next-payload : 8
type         : 2
protocol     : 17
port         : 500
length       : 10
ISAKMP (0): Total payload length: 14
return status is IKMP_NO_ERROR
crypto_isakmp_process_block: src 204.1.1.1, dest 203.1.1.1
OAK_QM exchange
oakley_process_quick_mode:
OAK_QM_IDLE
ISAKMP (0): processing SA payload. message ID = 1223411072
ISAKMP : Checking IPSec proposal 1
ISAKMP: transform 1, ESP_DES
ISAKMP:   attributes in transform:
ISAKMP:      encaps is 1
ISAKMP:      SA life type in seconds
ISAKMP:      SA life duration (basic) of 28800
ISAKMP:      SA life type in kilobytes
ISAKMP:      SA life duration (VPI) of  0x0 0x46 0x50 0x0 
ISAKMP:      authenticator is HMAC-MD5
ISAKMP (0): atts are acceptable.IPSEC(validate_proposal_request): proposal part #1,
(key eng. msg.) dest= 203.1.1.1, src= 204.1.1.1, 
dest_proxy= 10.1.1.0/255.255.255.0/0/0 (type=4), 
src_proxy= 10.2.2.0/255.255.255.0/0/0 (type=4),
protocol= ESP, transform= esp-des esp-md5-hmac , 
lifedur= 0s and 0kb, 
spi= 0x0(0), conn_id= 0, keysize= 0, flags= 0x4
ISAKMP (0): processing NONCE payload. message ID = 1223411072
ISAKMP (0): processing ID payload. message ID = 1223411072
ISAKMP (0): ID_IPV4_ADDR_SUBNET src 10.2.2.0/255.255.255.0 prot 0 port 0
ISAKMP (0): processing ID payload. message ID = 1223411072
ISAKMP (0): ID_IPV4_ADDR_SUBNET dst 10.1.1.0/255.255.255.0 prot 0 port
0IPSEC(key_engine): got a queue event...
IPSEC(spi_response): getting spi 0xd0e27cb6(3504503990) for SA from 204.1.1.1
to 203.1.1.1 for prot 3
return status is IKMP_NO_ERROR
crypto_isakmp_process_block: src 204.1.1.1, dest 203.1.1.1
OAK_QM exchange
oakley_process_quick_mode:
OAK_QM_AUTH_AWAIT
ISAKMP (0): Creating IPSec SAs
inbound SA from 204.1.1.1 to 203.1.1.1 proxy 10.2.2.0 to 10.1.1.0)
has spi 3504503990 and conn_id 4 and flags 4
lifetime of 28800 seconds
lifetime of 4608000 kilobytes
outbound SA from 203.1.1.1 to 204.1.1.1(proxy 10.1.1.0 to 10.2.2.0)
has spi 2729504033 and conn_id 3 and flags 4
lifetime of 28800 seconds
lifetime of 4608000 kilobytesIPSEC(key_engine): got a queue event...
IPSEC(initialize_sas): ,
(key eng. msg.) dest= 203.1.1.1, src= 204.1.1.1, 
dest_proxy= 10.1.1.0/255.255.255.0/0/0 (type=4), 
src_proxy= 10.2.2.0/255.255.255.0/0/0 (type=4),
protocol= ESP, transform= esp-des esp-md5-hmac , 
lifedur= 28800s and 4608000kb, 
spi= 0xd0e27cb6(3504503990), conn_id= 4, keysize= 0, flags= 0x4
IPSEC(initialize_sas): ,
(key eng. msg.) src= 203.1.1.1, dest= 204.1.1.1, 
src_proxy= 10.1.1.0/255.255.255.0/0/0 (type=4), 
dest_proxy= 10.2.2.0/255.255.255.0/0/0 (type=4),
protocol= ESP, transform= esp-des esp-md5-hmac , 
lifedur= 28800s and 4608000kb, 
spi= 0xa2b0ed21(2729504033), conn_id= 3, keysize= 0, flags= 0x4
return status is IKMP_NO_ERROR

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