实验拓扑：

拓扑说明：
1/名称说明：
Net云为通EVE-NG模拟器主机桥接的NAT网卡，负责该网络拓扑向外通信；ISP指代为运营商设备，BSW为边界交换机用于透传vlan和扩展接口，ASA为出口防火墙，CSW为核心交换机，ASW为介入交换机，DMZSW为DMZ网关交换机。
2/网段说明：
ISP1:100.100.100.x/30 ISP2:200.200.200.x/30 DMZ PAT地址为100.100.101.x/24 ,核心上联网段为10.10.10.x/24 ,核心下联网段为10.10.20.0/24和10.10.21.0/24，用户端为10.10.30.0/24，DMZ上联网段为172.16.10.0/24 ，服务器网段为172.16.20.0/24
3/关键功能点说明
①出口双线冗余自动切换，采用静态浮动路由的方式（默认ISP1为主）。
②防火墙双击冗余，采用failover Active/Standby 机制(默认ASA-A为主)。
③关键难点，在防火墙配置了AS模式后，主备防火墙配置是一模一样的，包括接口配置/路由配置/ACL/NAT等基础策略，当主防火墙在故障（宕机或者监控接口down ）在切换到备墙后上下联设备配置如何自动适应墙的主备切换。上联防火墙通过交换机vlan将2个墙的出口和对应线路的ISP网关组到了一个广播域中，无论是哪台墙工作都可以自动通ISP网关自适应,另外ISP提供的IP是极其有限的，我们不能在上联进行HSRP这样的冗余切换配置，只能是通过二层vlan通ISP网关打通（土豪无所谓）。对于下联我们就可以用HSRP的方式实现通墙切换的联动。注意这里有个小细节因为防火墙上联至二层和ISP 网关打通的所以切换过程中不涉及路由的切换，而下联是通过三层联动，这里会涉及路由的切换，如果同样也在墙中启用了动态路由协议那就不用考虑这个问题，但大多数情况下生产环境墙内是不会去跑路由协议的（墙主要职能是安全规则不是控制路由，静态完全游刃有余，而且清晰明了）。从核心层到用户网关层之间我们启用OSFP,核心到上联使用静态路由，所以这里上联的静态路由也需要加track,否则即使防火墙从A切换到B核心层上来的路由依旧会在CSW-1，然后再转发到CSW-2，在CSW-1静态路由中加入track ，引入OSPF时不添加always 参数，当ASA-A异常切换到ASA-B时，CSW-1中的track被触发，静态路由消失，CSW-1的OSPF中就不会向下发布默认路由，而CSW-2中的静态路由和CSW-1中的时一样的加track和相同的OSPF路由引入配置，这样就不会存在墙且到备以后，路由的横向折返，直接有主防火墙下联交换机下发默认路由，下联交换机直接转发数据包到对于的下一条。

二.设备核心配置

所有设备配置中均不包含二层/三层安全及调优/管理配置
ISP

• interface Ethernet0/0
  ip address dhcp
  !
  interface Ethernet0/1
  ip address 100.100.100.2 255.255.255.252
  !
  interface Ethernet0/2
  ip address 200.200.200.2 255.255.255.252

ip route 100.100.101.0 255.255.255.0 100.100.100.1
ip route 200.200.201.0 255.255.255.0 200.200.200.1
//以上配置为ISP中配置，路由为DMZ中做PAT pool的public IP

BSW

interface Port-channel10
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/0
switchport access vlan 100
switchport mode access
media-type rj45
negotiation auto
!
interface GigabitEthernet0/1
switchport access vlan 100
switchport mode access
media-type rj45
negotiation auto
!
interface GigabitEthernet0/2
switchport access vlan 200
switchport mode access
media-type rj45
negotiation auto
!
interface GigabitEthernet1/2
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode active
!
interface GigabitEthernet1/3
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode active
!

ASA-A

!
failover
failover lan unit primary
failover lan interface Folink GigabitEthernet0/5
failover polltime unit 1 holdtime 5
failover polltime interface msec 500 holdtime 25
failover polltime link-state msec 500
failover standby config-lock
failover link statelink GigabitEthernet0/6
failover interface ip Folink 2.2.2.1 255.255.255.252 standby 2.2.2.2
failover interface ip statelink 3.3.3.1 255.255.255.252 standby 3.3.3.2
failover ipsec pre-shared-key *****
!

interface GigabitEthernet0/0
nameif inside
security-level 100
ip address 10.10.10.1 255.255.255.0
!
interface GigabitEthernet0/1
nameif outside1
security-level 0
ip address 100.100.100.1 255.255.255.252
!
interface GigabitEthernet0/2
nameif outside2
security-level 0
ip address 200.200.200.1 255.255.255.252
!
interface GigabitEthernet0/3
nameif DMZ
security-level 80
ip address 172.16.10.1 255.255.255.252
!
interface GigabitEthernet0/5
description LAN Failover Interface
!
interface GigabitEthernet0/6
description STATE Failover Interface
!

!
object network InUsers
subnet 10.0.0.0 255.0.0.0
object network DMZ
subnet 172.16.0.0 255.255.0.0
object network Pub_DMZ
host 100.100.101.200
object service TCP_8080
service tcp destination eq 8080
object service TCP_80
service tcp destination eq www
object network DMZ_172.16.20.200
host 172.16.20.200
access-list inside_in extended permit icmp any any
access-list inside_in extended permit ip 10.0.0.0 255.0.0.0 any
access-list outside1_in extended permit icmp any any
access-list outside1_in extended permit ip any host 172.16.20.200
access-list outside2_in extended permit icmp any any
access-list outside2_in extended permit ip any host 172.16.20.200
access-list dmz_in extended permit icmp any any
access-list dmz_in extended permit ip object DMZ any
nat (any,DMZ) source static any any destination static Pub_DMZ DMZ_172.16.20.200 service TCP_8080 TCP_80
nat (inside,outside1) source dynamic InUsers interface
nat (DMZ,outside1) source dynamic DMZ interface
nat (inside,outside2) source dynamic InUsers interface
nat (DMZ,outside2) source dynamic DMZ interface
access-group inside_in in interface inside
access-group outside1_in in interface outside1
access-group outside2_in in interface outside2
access-group dmz_in in interface DMZ
route outside1 0.0.0.0 0.0.0.0 100.100.100.2 1 track 1
route outside2 0.0.0.0 0.0.0.0 200.200.200.2 10
route inside 10.0.0.0 255.0.0.0 10.10.10.2 1
route DMZ 172.16.0.0 255.255.0.0 172.16.10.2 1
!
!
sla monitor 1
type echo protocol ipIcmpEcho 100.100.100.2 interface outside1
timeout 1000
sla monitor schedule 1 life forever start-time now
!
!
track 1 rtr 1 reachability
!

ASA-B中只有failover配置略有不同，其他配置全部同步子ASA-A完全一致。
failover
failover lan unit secondary
failover lan interface Folink GigabitEthernet0/5
failover polltime unit 1 holdtime 5
failover polltime interface msec 500 holdtime 25
failover polltime link-state msec 500
failover standby config-lock
failover link statelink GigabitEthernet0/6
failover interface ip Folink 2.2.2.1 255.255.255.252 standby 2.2.2.2
failover interface ip statelink 3.3.3.1 255.255.255.252 standby 3.3.3.2
failover ipsec pre-shared-key *****

PS:在防火墙的部署中，在开机零配置的情况下最后保证2台设备完全一致，首先分别配置failover，之后所有配置只需在主墙中配置即可。

ASDM配置

CSW-1

!
interface Port-channel10
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/0
switchport access vlan 1000
switchport mode access
media-type rj45
negotiation auto
!
!
interface GigabitEthernet0/1
no switchport
ip address 10.10.20.1 255.255.255.252
negotiation auto
!
!
interface GigabitEthernet1/2
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode on
!
interface GigabitEthernet1/3
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode on
!
!
interface Vlan1000
ip address 10.10.10.3 255.255.255.0
standby 10 ip 10.10.10.2
standby 10 priority 200
standby 10 preempt
standby 10 track 1 decrement 50
!

!
router ospf 1
router-id 10.10.10.3
network 10.10.10.0 0.0.0.255 area 0
network 10.10.20.0 0.0.0.255 area 0
default-information originate metric-type 1
!
!
ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 1
!
!
ip sla 1
icmp-echo 10.10.10.1 source-ip 10.10.10.3
frequency 5
ip sla schedule 1 life forever start-time now
!
!
track 1 ip sla 1 reachability
!

CSW-B

!
interface Port-channel10
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet0/0
switchport access vlan 1000
switchport mode access
media-type rj45
negotiation auto
!

!
interface GigabitEthernet0/1
no switchport
ip address 10.10.21.1 255.255.255.252
negotiation auto
!
!
interface GigabitEthernet1/2
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode on
!
interface GigabitEthernet1/3
switchport trunk encapsulation dot1q
switchport mode trunk
media-type rj45
negotiation auto
channel-group 10 mode on
!
!
interface Vlan1000
ip address 10.10.10.4 255.255.255.0
standby 10 ip 10.10.10.2
standby 10 priority 180
!

!
router ospf 1
router-id 10.10.10.4
network 10.10.10.0 0.0.0.255 area 0
network 10.10.21.0 0.0.0.255 area 0
default-information originate metric 1 metric-type 1
!
!
ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 1
!
!
ip sla 1
icmp-echo 10.10.10.1 source-ip 10.10.10.4
frequency 5
ip sla schedule 1 life forever start-time now
!
!
track 1 ip sla 1 reachability
!

ASW-1

!
ip dhcp pool users
network 10.10.30.0 255.255.255.0
dns-server 223.5.5.5 114.114.114.114
default-router 10.10.30.254
!
!
interface GigabitEthernet0/2
switchport access vlan 30
switchport mode access
media-type rj45
negotiation auto
spanning-tree portfast edge
!
!
interface GigabitEthernet0/0
no switchport
ip address 10.10.20.2 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/1
no switchport
ip address 10.10.21.2 255.255.255.252
negotiation auto
!
!
router ospf 1
router-id 10.10.20.2
network 10.10.20.0 0.0.0.255 area 0
network 10.10.21.0 0.0.0.255 area 0
network 10.10.30.0 0.0.0.255 area 0
!

DMZSW-1

!
interface GigabitEthernet0/0
switchport access vlan 10
switchport mode access
media-type rj45
negotiation auto
!
interface GigabitEthernet0/1
switchport access vlan 10
switchport mode access
media-type rj45
negotiation auto
!
interface GigabitEthernet0/2
switchport access vlan 20
switchport mode access
media-type rj45
negotiation auto
spanning-tree portfast edge
!
!
interface Vlan10
ip address 172.16.10.2 255.255.255.252
!
interface Vlan20
ip address 172.16.20.254 255.255.255.0
!

!
ip route 0.0.0.0 0.0.0.0 172.16.10.1
!

三.切换验证
1.出口切换
切换前：


再ISP中关闭线路1接口切换后：




在线路切换中正常业务丢包大约在4-8个包左右。
2.防火墙HA
切换前：


重启ASA-A切换后：


切换只丢1个包。
PS:这里在做验证的时候又发现了一个小问题，就是在已经做完上面线路出口切换的情况下不会退，再来进行HA的切换演练，会存在一个问题，但HA切换以后ASA-B中的默认路由依旧还是线路1的，而线路1在实验室已经down了，这就会导致切换后出现问题，解决办法就是清理路由表缓存 clear route all （或者指定下一条，生产中最后最小清除），这时候就会切换到线路2 ，同样在做线路切换模拟时，ASA-A 中的路由刷新等待时间时比较久的，这时候也可以手动刷新加快收敛速度。

四.遗留问题
1.上面虽然用手动刷新了路由表解决了这个缓存的问题，但在实际环境中这种切换时随机发生，我们不可能立马发现并受到刷新，所以如何避免因为路由缓存而影响HA切换故障时效时后面考虑的一个点。
2.在上面的拓扑中存在一个缺陷即核心时单上联防火墙，所以当主核心宕机而防火墙正常的情况下，数据是没有办法上行的，这里必须要进行双上联，否则双核心没有任何意义。
3.对于DMZ区域的NAT，在配置PAT的时候要注意PAT配置的顺序要优于DMZ NAT的顺序，否则PAT无法生效，具体参考另一篇文章https://blog.51cto.com/pinglife/2507602

由于时间有限，行文潦草，还缺少很多细节，后续再做完善。

CISCO ASA防护墙详细AS/双出口配置切换---By 年糕泰迪