2023年6月26日发(作者：)

ROUTE-POLICY 路由策略 规则详解

在实际工程中经常用到route-policy的情况，下面对route-policy和ACL的详细匹配规则做以说明：

一、 标准访问列表：

#

acl number 2000

rule 0 permit source 192.168.1.0 0.0.0.255

此类ACL用于route-policy时做前缀匹配，即路由条目和规则条目做 AND 运算 ，结果落在反掩码的包含范围之内的则匹配成功。

对于上述配置：192.168.1.0/24 192.168.1.0 /25 192.168.1.0/30 等均可匹配，但是192.168.1.0/16 等则匹配不成功。

二、 扩展访问列表：

#

acl number 3000

rule 0 permit ip source 192.168.1.0 0 destination 255.255.255.0 0

acl number 3001

rule 0 deny ip source 192.168.1.0 0 destination 255.255.255.0 0

此类ACL比较特殊，源和目的的掩码均要为0 。用于route-policy 是要做严格的匹配，即前缀要和source 匹配，前缀的掩码部分要和destination匹配。

对于上述配置3000来说，则只有192.168.1.0/24可与之匹配。此类列表和Route-policy配合可用于严格的匹配一条路由条目。

三、 permit+permit的route-policy

#

route-policy t1 permit node 10

if-match acl 3000

apply local-preference 1300

route-policy t1 permit node 20

对于route-policy的permit规则来说，凡是能够匹配ACL permit规则的条目就执行node 10中的apply 规则，并不再继续匹配下面的规则。不能够匹配ACL permit规则的条目，就继续执行下一个 node 20中的相应规则。

对于上述配置的结果是192.168.1.0/24匹配node 10 被修改LP属性为1300 ，而192.168.2.0/24 则匹配node 20 不做任何修改。2个条目都可以通告。

[AR2810-B]dis bgp routing

Flags: # - valid ^ - active I - internal

D - damped H - history S - aggregate suppressed

Dest/Mask Next-Hop Med Local-pref Origin Path

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

#^I 192.168.1.0 10.0.0.2 0 1300 IGP

#^I 192.168.2.0 10.0.0.2 0 100 IGP Routes total: 2

[AR2810-B]

四、 permit+deny 的route-policy

#

route-policy t2 permit node 10

if-match acl 3001

apply local-preference 2300

route-policy t2 permit node 20

对于route-policy 的permit规则来说，凡是明确和ACL 的deny 规则匹配的则不执行node 10中的apply规则。并且会继续执行下一个node 20 进行匹配 。

对于上述配置的结果是：192.168.1.0/24 和node 10 匹配，被 DENY 。但是会继续和后面的nod 20 匹配 。上述规则192.168.1.0/24 192.168.2.0/24条目都可被通告。

[AR2810-B]dis bgp routing

Flags: # - valid ^ - active I - internal

D - damped H - history S - aggregate suppressed

Dest/Mask Next-Hop Med Local-pref Origin Path

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

#^I 192.168.1.0 10.0.0.2 0 100 IGP

#^I 192.168.2.0 10.0.0.2 0 100 IGP

Routes total: 2

[AR2810-B]

五、 deny+permit 的route-policy

#

route-policy t3 deny node 10

if-match acl 3000

apply local-preference 1300

route-policy t3 permit node 20

对于route-policy的deny规则来说，凡是和ACL的permit规则匹配的条目都被DENY掉。未匹配的条目则继续向下匹配。

对于上述配置的结果是：192.168.1.0/24和node 10 匹配，被DENY 掉。而192.168.2.0/24则和node 20 匹配。上述规则只有192.168.2.0/24可被通告。

[AR2810-B]dis bgp routing

Flags: # - valid ^ - active I - internal

D - damped H - history S - aggregate suppressed

Dest/Mask Next-Hop Med Local-pref Origin Path

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

#^I 192.168.2.0 10.0.0.2 0 100 IGP

Routes total: 1

[AR2810-B]

六、 deny+deny 的 route-policy

#

route-policy t4 deny node 10

if-match acl 3001

apply local-preference 2300

route-policy t4 permit node 20

对于route-policy的Deny规则来说，凡是和ACL 的deny规则明确匹配的条目被node

10 Deny，并且向下继续匹配后续的规则。这就产生了双重DENY 变成 permit的效果。

对于上述配置的结果是：192.168.1.0/24 192.168.2.0/24 都和node 20匹配。即都可发布。

[AR2810-B]dis bgp routing

Flags: # - valid ^ - active I - internal

D - damped H - history S - aggregate suppressed

Dest/Mask Next-Hop Med Local-pref Origin Path

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

#^I 192.168.1.0 10.0.0.2 0 100 IGP

#^I 192.168.2.0 10.0.0.2 0 100 IGP

Routes total: 2

[AR2810-B]

对于上述论述总结如下如下：

1、route-policy 中的DENY 和applay配合无任何意义。

2、凡是在ACL 中被DENY过的条目，可以继续向下匹配。

3、在route-policy中被DENY 匹配过的条目则被DENY 不会继续匹配。 4、Route-policy用于路由策略时有一个隐含的规则为DENY ALL ，而用于策略路由时则是PERMIT ALL

附件1：

一、 实验相关信息

A (s3/0) ---------(S3/0) B

1）本次测试中用到的设备为H3C AR2810 相关版本及配置信息如下:

AR2810-A:

[AR2810-A]dis ver

Huawei Versatile Routing Platform Software

VRP software, Version 3.40, Release 0201P29

Copyright (c) 1998-2008 Huawei Technologies Co., Ltd. All rights reserved.

Without the owner's prior written consent, no decompiling

nor reverse-engineering shall be allowed.

Quidway AR28-10 uptime is 0 week, 0 day, 1 hour, 13 minutes

Last reboot 2008/11/28 06:04:07

System returned to ROM By Command.

CPU type: PowerPC 8241 200MHz

128M bytes SDRAM Memory

32M bytes Flash Memory

PCB Version:4.0

Logic Version:1.0

BootROM Version:9.23

[SLOT 0] AUX (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 0] 1FE (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 0] WAN (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 3] 1SA (Hardware)1.0, (Driver)1.0, (CPLD)2.0

[AR2810-A]vrbd

Routing Platform Software

Version AR28-10 8040V300R003B04D040SP73

(COMWAREV300R002B62D014), RELEASE SOFTWARE

Compiled Oct 22 2008 18:24:10 by jiahua

[AR2810-A]dis cu

[AR2810-A]dis current-configuration

#

sysname AR2810-A

#

acl number 2000

rule 0 permit source 192.168.1.0 0.0.0.255

#

acl number 3000 rule 0 permit ip source 192.168.1.0 0 destination 255.255.255.0 0

acl number 3001

rule 0 deny ip source 192.168.1.0 0 destination 255.255.255.0 0

#

interface Serial3/0

link-protocol ppp

ip address 10.0.0.2 255.255.255.252

#

bgp 100

network 192.168.1.0

network 192.168.2.0

undo synchronization

group tolocal internal

peer tolocal route-policy t4 export

peer 10.0.0.1 group tolocal

#

route-policy t1 permit node 10

if-match acl 3000

apply local-preference 1300

route-policy t1 permit node 20

route-policy t2 permit node 10

if-match acl 3001

apply local-preference 2300

route-policy t2 permit node 20

route-policy t3 deny node 10

if-match acl 3000

apply local-preference 1300

route-policy t3 permit node 20

route-policy t4 deny node 10

if-match acl 3001

apply local-preference 2300

route-policy t4 permit node 20

#

ip route-static 192.168.1.0 255.255.255.0 NULL 0 preference 60

ip route-static 192.168.2.0 255.255.255.0 NULL 0 preference 60

[AR2810-A]

Ar2810-B:

[AR2810-B]dis ver

Huawei Versatile Routing Platform Software

VRP software, Version 3.40, Release 0201P29

Copyright (c) 1998-2008 Huawei Technologies Co., Ltd. All rights reserved.

Without the owner's prior written consent, no decompiling

nor reverse-engineering shall be allowed.

Quidway AR28-10 uptime is 0 week, 0 day, 1 hour, 13 minutes Last reboot 2021/08/22 01:14:25

System returned to ROM By Command.

CPU type: PowerPC 8241 200MHz

128M bytes SDRAM Memory

32M bytes Flash Memory

PCB Version:4.0

Logic Version:1.0

BootROM Version:9.23

[SLOT 0] AUX (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 0] 1FE (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 0] WAN (Hardware)4.0, (Driver)1.0, (CPLD)1.0

[SLOT 3] 1SA (Hardware)1.0, (Driver)1.0, (CPLD)2.0

[AR2810-B]vrbd

Routing Platform Software

Version AR28-10 8040V300R003B04D040SP73

(COMWAREV300R002B62D014), RELEASE SOFTWARE

Compiled Oct 22 2008 18:24:10 by jiahua

[AR2810-B] dis cu

#

sysname AR2810-B

#

interface Serial3/0

clock DTECLK1

link-protocol ppp

ip address 10.0.0.1 255.255.255.252

#

bgp 100

undo synchronization

group tolocal internal

peer 10.0.0.2 group tolocal

[AR2810-B]

2）将上述拓扑中的路由器A 替换成CISCO 3640 。再次重复以上试验，得出结论与H3C的route-policy相同。相关CISCO设备版本及配置如下：

C3640#show ver

Cisco Internetwork Operating System Software

IOS (tm) 3600 Software (C3640-IK9O3S-M), Version 12.2(SOFTWARE (fc1)

TAC Support: /tac

Copyright (c) 1986-2003 by cisco Systems, Inc.

T10, RELEASE Compiled Sat 31-May-03 00:17 by kellythw

Image text-base: 0x60008930, data-base: 0x6171C000

ROM: System Bootstrap, Version 11.1(20)AA1, EARLY DEPLOYMENT RELEASE

SOFTWARE (fc1)

C3640 uptime is 16 minutes

System returned to ROM by reload

System image file is "flash:"

cisco 3640 (R4700) processor (revision 0x00) with 125952K/5120K bytes of

memory.

Processor board ID 13894963

R4700 CPU at 100Mhz, Implementation 33, Rev 1.0

Bridging software.

X.25 software, Version 3.0.0.

SuperLAT software (copyright 1990 by Meridian Technology Corp).

5 Ethernet/IEEE 802.3 interface(s)

4 Serial network interface(s)

DRAM configuration is 64 bits wide with parity disabled.

125K bytes of non-volatile configuration memory.

16384K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

C3640#show running-config

!

hostname C3640

!

interface Serial1/1

ip address 10.0.0.2 255.255.255.0

encapsulation ppp

serial restart_delay 0

!

router bgp 100

no synchronization

bgp log-neighbor-changes

network 192.168.1.0

network 192.168.2.0

neighbor 10.0.0.1 remote-as 100

neighbor 10.0.0.1 route-map t4 out

no auto-summary

!

ip classless ip route 192.168.1.0 255.255.255.0 Null0

ip route 192.168.2.0 255.255.255.0 Null0

no ip http server

ip pim bidir-enable

!

!

access-list 101 permit ip host 192.168.1.0 host 255.255.255.0

access-list 102 deny ip host 192.168.1.0 host 255.255.255.0

!

route-map t4 deny 10

match ip address 102

set local-preference 1300

!

route-map t4 permit 20

!

route-map t1 permit 10

match ip address 101

set local-preference 1300

!

route-map t1 permit 20

!

route-map t2 permit 10

match ip address 102

set local-preference 1300

!

route-map t2 permit 20

!

route-map t3 deny 10

match ip address 101

set local-preference 1300

!

route-map t3 permit 20

C3640#