NAT & Local Policy Based Routing's Question !!

From: wwwjjang@chol.com
Date: Sun Aug 10 2003 - 11:48:53 GMT-3


Hi! Everyone..

I was confused by this question..
Who knows the solution ??
---------
Diagram
---------
(e01.1.1.1)-R2-(so2.2.2.2)-(so2.2.2.1)-R1-(e01.1.1.3)-(e01.1.1.14)-R3
              |______________________OSPF__________________________|

Note:
- The R2's E0-Net(1.1.1.0/24) is same with the Ethernet-Network between R1
& R3 (1.1.1.0/24)
-R2's E0 is not covered with a OSPF & is a Private-network !!

__________
Question
----------
1> Make Sure that R2'E0-Network can communicate with ouside.
2> Make sure that you can send a ping to the R2's S0(2.2.2.2) with a source ip
   1.1.1.14(R3,s E0) and receive a echo-reply from R2's E0(1.1.1.1)

----------
My answer
----------
1> First, i configure a NAT on R2.(it operates well !!)

R2>
interface Ethernet0
 ip address 1.1.1.1 255.255.255.0
 ip nat inside
!
interface Serial1
 ip address 2.2.2.2 255.255.255.0
 ip nat outside
!
ip nat inside source route-map NAT interface serial 0 overload
access-list 20 permit 1.1.1.0 0.0.0.255
!
route-map NAT permit 10
 match ip address 20

2> When i send a ping to the R2's s0, i can't receive a echo-reply.
   Since the R2's E0-Network(1.1.1.0/24) is same with the Ethernet-Network
   between R1 & R3, The echo-reply packet is sended to the R2'E0.
   So the echo-reply packet is dropped.
   (Can you understand my explanation ???)

   So i think that the local policy-map on R2 is a one of the solutins.
   
R2>

ip local policy route-map POL
route-map POL permit 10
 match ip add 150
 set ip next-hop 2.2.2.1
access-list 150 permit icmp any any

=> So, when i send a ping to the R2's S0(2.2.2.2) with a source R3'e0(1.1.1.14),
       i can receive a echo-reply from R2's E0(1.1.1.1)!!!!
=> But the NAT don't work. !!!
   When i remove the Local policy-map, The NAT works well !!

Do you know the reason of this problem???
How can i solve the two-questions ??

Thanks !!



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