一.概述：
QQ羣裏面有網友討論ASA防火牆的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範圍是不一樣的，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，爲了確認自己的想法，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先後調用執行，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執行範圍是不一樣的，估計接口的policy-map會被優先調用執行，順序可能爲：
①.先執行接口的service-policy，並調用對應的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，則會接着執行全局的service-policy，並調用對應的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，或者被審查後丟棄。
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服務器端口爲：2000
四.基本配置：
A.PC1:
IP:10.1.1.8/24 ,GW:10.1.1.1
B.ASA842防火牆：
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，因爲默認全局策略開啓了skinny審查
B.配置outside接口的policy-map並調用：
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審查合格後放行，但是卻被全局下的class-map丟棄。
D.調整outside接口的policy-map並調用：
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，訪問完成之後再查看：
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
----可以發現訪問前後全局和接口的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，因爲outside的ACL沒有明確拒絕流量，所以被匹配，並檢測到不是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配置了拒絕後，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，或審查後被丟棄，都不會去匹配全局policy-map