ASA8.4policy-map接口和全局執行的優先級測試：

一.概述：

   QQ群里面有網友討論ASA防火墻的policy-map的global和interface的執行順序，從字面意思可以看出這兩種的應用范圍是不一樣的，一個是全局調用，一個只在接口下調用，因此覺得是詳細的interface被優先調用，為了確認自己的想法，決定搭建環境驗證一下。

二.基本思路：

A.不相沖突的policy-map估計會被全局和接口的service-policy先后調用執行，看不出效果
B.只能用相沖突的policy-map，在全局和接口的service-policy中同時調用，看最終哪個生效
C.全局和接口的policy-map執行范圍是不一樣的，估計接口的policy-map會被優先調用執行，順序可能為：
①.先執行接口的service-policy，并調用對應的policy-map，如果被匹配，則不執行全局的service-policy
②.如果不被接口的policy-map所匹配，則會接著執行全局的service-policy，并調用對應的policy-map
----經過測試，發現跟想象的有點區別：如果被接口policy-map審查通過，是會送到全局policy-map的；除非被接口的class-map的ACL丟棄，或者被審查后丟棄。

三.測試拓撲：
        10.1.1.0/24(Inside)                  200.100.1.0/24(Outside)
PC1(.8)----------------------(.1)ASA842(.1)----------------------------(.8)PC2
                                                                     web服務器端口為：2000

四.基本配置：

A.PC1:

IP:10.1.1.8/24 ,GW:10.1.1.1

B.ASA842防火墻：

①接口配置：

interface GigabitEthernet0
nameif Inside
security-level 100
ip address 10.1.1.1 255.255.255.0

no shut

interface GigabitEthernet1
nameif Outside
security-level 0
ip address 202.100.1.1 255.255.255.0
no shut

②動態PAT配置：

object network Inside.net
subnet 10.1.1.0 255.255.255.0
object network Inside.net
nat (Inside,Outside) dynamic interface

③靜態PAT配置：

object network Inside.pc1
host 10.1.1.8
object network Inside.pc1
nat (Inside,Outside) static interface service tcp 2000 2000

④策略設置：

access-list outside extended permit tcp any object Inside.pc1 eq 2000
access-group outside in interface Outside

五.測試步驟：

A.驗證此時外網是否能正常訪問內部web服務器：

----無法訪問，因為默認全局策略開啟了skinny審查

B.配置outside接口的policy-map并調用：

access-list web2000 extended permit tcp any object Inside_pc1 eq 2000

class-map web2000
match access-list web2000

policy-map web2000
class web2000
 inspect http
service-policy web2000 interface Outside

C.驗證此時外網是否能正常訪問內部web服務器：

---仍然無法訪問

ciscoasa# show service-policy
Global policy:
 Service-policy: global_policy
   Class-map: inspection_default
     .....省略部分..................
     Inspect: ip-options _default_ip_options_map, packet 0, drop 0, reset-drop 0
     Inspect: skinny , packet 4, drop 1, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0
Interface Outside:
 Service-policy: web2000
   Class-map: web2000
     Inspect: http, packet 4, drop 0, reset-drop 0

---可以看到，數據包雖然被接口下class-map審查合格后放行，但是卻被全局下的class-map丟棄。

D.調整outside接口的policy-map并調用：

access-list outside_skinny extended deny tcp any object Inside_pc1 eq 2000
access-list outside_skinny extended permit tcp any any eq 2000

class-map outside_skinny
match access-list outside_skinny

policy-map outside_skinny
class outside_skinny
 inspect skinny  

no service-policy web2000 interface outside

service-policy outside_skinny interface Outside

E.驗證此時外網是否能正常訪問內部web服務器：

---可以正常訪問

訪問之前，clear  service-policy，訪問完成之后再查看：

ciscoasa# show service-policy
Global policy:
 Service-policy: global_policy
   Class-map: inspection_default
     .....省略部分..................

     Inspect: ip-options _default_ip_options_map, packet 0, drop 0, reset-drop 0
     Inspect: skinny , packet 0, drop 0, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0
Interface Outside:
 Service-policy: outside_skinny
   Class-map: outside_skinny
     Inspect: skinny , packet 0, drop 0, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0

----可以發現訪問前后全局和接口的class-map都沒有被匹配

F.調整全局和接口policy-map：

①接口：

access-list outside_skinny extended permit tcp any any eq 2000

class-map outside_skinny
match access-list outside_skinny

policy-map outside_skinny
class outside_skinny
 inspect skinny  
service-policy outside_skinny interface Outside

②全局：

access-list global_skinny extended deny tcp any object Inside_pc1 eq 2000
access-list global_skinny extended permit tcp any any eq 2000
class-map global_skinny
match access-list global_skinny
policy-map global_policy
class inspection_default
 no inspect skinny
class global_skinny
service-policy global_policy global

③測試:

----無法訪問，被outside接口的policy-map拒絕

ciscoasa# show service-policy
Global policy:
 Service-policy: global_policy
   Class-map: inspection_default
     ........省略部分..............
     Inspect: ip-options _default_ip_options_map, packet 0, drop 0, reset-drop 0
   Class-map: global_skinny
     Inspect: skinny , packet 0, drop 0, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0
Interface Outside:
 Service-policy: outside_skinny
   Class-map: outside_skinny
     Inspect: skinny , packet 4, drop 1, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0

----可以看到，因為outside的ACL沒有明確拒絕流量，所以被匹配，并檢測到不是skinny流量而被丟棄

G.再次調整全局和接口的policy-map：

①接口：

access-list outside_skinny extended deny tcp any object Inside_pc1 eq 2000

access-list outside_skinny extended permit tcp any any eq 2000
class-map outside_skinny
match access-list outside_skinny
policy-map outside_skinny
class outside_skinny
 inspect skinny  
service-policy outside_skinny interface Outside

②全局：

access-list global_skinny extended permit tcp any any eq 2000

class-map global_skinny
match access-list global_skinny

policy-map global_policy

class global_skinny
 inspect skinny  
service-policy global_policy global

③測試:

----可以正常訪問

ciscoasa# show service-policy

Global policy:
 Service-policy: global_policy
   Class-map: inspection_default
     .......省略部分....................
     Inspect: ip-options _default_ip_options_map, packet 0, drop 0, reset-drop 0
   Class-map: global_skinny
     Inspect: skinny , packet 0, drop 0, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0
Interface Outside:
 Service-policy: outside_skinny
   Class-map: outside_skinny
     Inspect: skinny , packet 0, drop 0, reset-drop 0
              tcp-proxy: bytes in buffer 0, bytes dropped 0

----可以發現outside接口的ACL配置了拒絕后，不會去匹配全局的policy-map。

六.總結：

A.處理順序：先接口再全局

B.是否會送到全局：如果沒有被接口policy-map匹配，或被接口policy-map審查通過，會被送到全局

-----被ACL丟棄，或審查后被丟棄，都不會去匹配全局policy-map