how to make condition natting if an icmp ping failed ??

[Dr.X]

hi ,

assume i have pc with ip 1.1.1.1

note that pc can reach internet with ip 1.1.1.1

connected with  router as below :

pc----------------router-------------------switch----------------internet

on router , i want to set condition ,

if ping  on 8.8.8.8 failed  from router , i want  router to nat the ip 1.1.1.1 to ip 2.2.2.2

how to do that ??????

regards

[Reza Sharifi]

Hi,

1.1.1.1 and 2.2.2.2 are both public IP segments.  Usually NAT is done for private IP segments. 

Here is good doc to read on conditional NAT:

http://www.cisco.com/en/US/docs/security/asa/asa82/configuration/guide/nat_static.html#wp1074755

HTT

[Dr.X]

hi , im just getting ips 1.1.1.1 2.2.2.2 as an exapmles ,

i just ask about conditional nat ,

thanks alot , i will read it and   discuss with u

regards

[Dr.X]

im looking about creating ip sla  and  define  icmp echo time out , and when this condition occurs i want to perform the natting ,

i searched but ddint find any about my goal !

regards

[Carlo Poggiarelli]

Hi.
Is the out interface the same even if ping would fail?
Let me know

Regards
Carlo

Sent from Cisco Technical Support iPhone App

[Dr.X]

hi ,

to make more explanation ,

i have two isp gateways using bgp protocol ,

here is simple topology

lan network=======routerx========switch=======gateway router1==========isp1

                                                                                                 |

                                                                                                 |

                                                                                                 |

                                                                                              isp2

now on lan network i have assume i have  two subnets

subnet 1  advertised to isp1 assume 1.1.1.0/24

subnet 2  advertised to sip2      2.2.2.0/24

note that on

gateway router1

im performing  route map so that subnet 1  go to isp1  and subnet 2  go to isp2

===============================================

now  lets go to my issue ,

assume that isp1 failed , or  " ping from src ip of 1.1.1.1 to 8.8.8.8" failed !!!!

i want some hosts of subnet 1.1.1.0/24 to  go internet from isp2 ,

this is my clear issue

i mean that off my work will be on routerx

how connect  nating with ip sla ??? 

regards

[Carlo Poggiarelli]

Hi.

You can try to work with next-hop availability based on ip sla.

Please give a look to this doc

https://supportforums.cisco.com/docs/DOC-8313

HTH

Regards.

Carlo

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"The more you help the more you learn"

[Dr.X]

hi  ,

i know about  route map  and its integration with next hop availability but i need natting in this case .

each subnet is only advertied to  its isp ,

regards

[Carlo Poggiarelli]

Hi.
If you read that doc you can apply nat based on next hop reachability even using ip sla.
If the first route map does not satisfy the condition , because of track object down, you can apply nat based on second route map configuring
ip nat pool ISP-B 2.2.2.2 2.2.2.2 netmask 255.255.255.252

ip nat inside source route-map ispb pool ISP-B overload.

HTH
Regards

Carlo

Sent from Cisco Technical Support iPhone App

[Dr.X]

hi all ,

plz pay attention to my config and tell me why it always  doing nat ??!!!

i mean it always doing nat  whatever the track was up or down ,

here is my config below :

lan====>ip nat inside=routerx==>ip nat outside======switch=======gateway router1==========isp1

                                                                                                 |

                                                                                                 |

                                                                                                 |

                                                                                              isp2

ip nat pool tod x.x.111.1 x.x.111.30 netmask 255.255.255.224

ip nat inside source route-map natprtg pool tod

ip access-list extended natprtg

permit ip host zzzzz any

======================================================

Gateway7600#sh route-map

route-map natprtg, permit, sequence 10

  Match clauses:

    ip address (access-lists): natprtg

  Set clauses:

    ip next-hop verify-availability 172.30.40.1 50 track 5  [up]

  Policy routing matches: 86750 packets, 11236147 bytes

========================================================

sh ip nat translations===> natting  found

now when track is down :

Gateway7600#sh route-map

route-map natprtg, permit, sequence 10

  Match clauses:

    ip address (access-lists): natprtg

  Set clauses:

    ip next-hop verify-availability 172.30.40.1 50 track 5  [down]

  Policy routing matches: 86750 packets, 11236147 bytes

when i type show ip nat trans  natting still found !!!!???????/

why ??????/