可见B4已经根据B1的源来转发数据包，注意：record功能来验证是验证不出来的，因为record根据表的转发接口来记录。
查看B4的logging信息：
*Mar 1 00:58:00.179: IP: s=.1 (Serial1), d=3.3.3.3, len 28, policy match
*Mar 1 00:58:00.183: IP: route map to-B9, item 10, permit
*Mar 1 00:58:00.187: IP: s=.1 (Serial1), d=3.3.3.3 (Serial0), len 28, poli
cy routed
*Mar 1 00:58:00.191: IP: Serial1 to Serial0 .3
*Mar 1 00:58:00.239: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:03.243: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:06.247: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:09.251: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:12.255: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:15.259: IP: s=.1 (Serial1), d=255.255.255.255, len 67, polic
y rejected -- normal forwarding
*Mar 1 00:58:18.259: IP: s=.1 (Serial1), d=3.3.3.3, len 28, policy match
*Mar 1 00:58:18.263: IP: route map to-B9, item 10, permit
*Mar 1 00:58:18.263: IP: s=.1 (Serial1), d=3.3.3.3 (Serial0), len 28, pol
*Mar 1 00:58:18.267: IP: Serial1 to Serial0 .3
*Mar 1 00:58:18.303: IP: s=.1 (Serial1), d=3.3.3.3, len 28, policy match
*Mar 1 00:58:18.307: IP: route map to-B9, item 10, permit
*Mar 1 00:58:18.311: IP: s=.1 (Serial1), d=3.3.3.3 (Serial0), len 28, poli
cy routed
*Mar 1 00:58:18.315: IP: Serial1 to Serial0 .3
接下，我们再进一在B9验证返回路径：
B9#traceroute
Protocol [ip]:
Target IP address: .1
Source address: .3
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to .1
1 213.1.1.2 16 msec 16 msec 20 msec
2 .1 36 msec 36 msec *
可见返回的路径仍然是通过以太网接口，如要求B1访问B9是原路返回方式（通过B9的serial 0），同样采用PBR（policy Based Routing路由）的方式，需在B9上面做配置：
B4（config）#access-list 10 permit .0 0.0.0.255
用route-map引用访问列表，设置下一跳：
B4(config)#route-map to-B1
B4(config-route-map)#match ip address 10
B4(config-route-map)#set ip next-ho.2
在接口下应用策略：
B4(config)#interface loop 0
B4(config-if)#ip policy route-map to-B9
这样的配置使不会起效的，本产生的数据包默认不会基于策略进行路由。 B9#traceroute
Protocol [ip]:
Target IP address: .1
Source address: .3
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to .1
1 213.1.1.2 4 msec 4 msec 4 msec
2 .1 28 msec 24 msec *
需启用命令，使路由器对它产生的数据包进行策略路由。
B9#traceroute
Protocol [ip]:
Target IP address: .3
Source address: .1
% Invalid source address
B9#t
B9#tr
B9#traceroute
Protocol [ip]:
Target IP address: .1
Source address: .3
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to .1
1 .2 8 msec 8 msec 12 msec
2 .1 32 msec 28 msec *
以上已经验证了策略路由基于源IP的方式，在不匹配策略路由的情况下，则仍按照路由表方式转发数据报文。
B4#ping
Protocol [ip]:
Target IP address: .3
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: .1
% Invalid source. Must use IP address or full interface name without spaces (e.g
. Serial0/1)
Source address or interface:
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to .3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/19/20 ms
然后查看B4的logging，一下为不符合策略转发范围，仍找普通的方式转发：
B4#show logging
*Mar 1 01:35:10.335: IP: s=.1 (Serial1), d=3.3.3.3 (Ethernet0), len 100, p
olicy rejected -- normal forwarding
*Mar 1 01:35:10.395: IP: s=.1 (Serial1), d=3.3.3.3 (Ethernet0), len 100, p
olicy rejected -- normal forwarding
*Mar 1 01:35:10.447: IP: s=.1 (Serial1), d=3.3.3.3 (Ethernet0), len 100, p
olicy rejected -- normal forwarding
*Mar 1 01:35:10.503: IP: s=.1 (Serial1), d=3.3.3.3 (Ethernet0), len 100, p
olicy rejected -- normal forwarding
*Mar 1 01:35:10.555: IP: s=.1 (Serial1), d=3.3.3.3 (Ethernet0), len 100, p
olicy rejected -- normal forwarding
策略路由在接口应用后处理数据包转发优先于路由表，即使路由表没有对应路由条目，单纯用策略路由也能正常转发数据包。