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Community Member

NAT translation failed


NAT isn't working on a router after an IP addressing change. When I try to use NAT with nat debugging enabled, I get the following message in the logs:

NAT: translation failed (A), dropping packet s=local_ip d=remote_ip

On Cisco website, I found that "A" means the packets was dropped after routing process, but no useful information with this error message.


! Access-list 101 is used by NAT

! We deny packets directed to through the NAT (they must go through an IPSec tunnel)

access-list 101 deny ip

access-list 101 permit ip any

ip nat inside source list 101 interface ATM0.1 overload

interface Loopback0

ip address x.x.x.x

interface Ethernet0

ip address

ip nat inside

no cdp enable

hold-queue 100 out

interface ATM0

no ip address

no ip mroute-cache

load-interval 30

no atm ilmi-keepalive

dsl operating-mode auto

dsl power-cutback 0

hold-queue 224 in

interface ATM0.1 point-to-point

ip unnumbered Loopback0

ip nat outside

crypto map FOO

pvc 2/32

ubr 320

encapsulation aal5mux ip

additional informations:

#sh access-lists 101

Extended IP access list 101

deny ip (30027 matches)

permit ip any (4521 matches)

#sh ip nat statistics

Total active translations: 0 (0 static, 0 dynamic; 0 extended)

Outside interfaces:


Inside interfaces:


Hits: 0 Misses: 0

Expired translations: 0

Dynamic mappings:

-- Inside Source

[Id: 1] access-list 101 interface ATM0.1 refcount 0

#sh ver

Cisco Internetwork Operating System Software

IOS (tm) C837 Software (C837-K9O3SY6-M), Version 12.2(8)YN, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

Synched to technology version 12.2(11.2u)T

TAC Support:

Copyright (c) 1986-2002 by cisco Systems, Inc.

Compiled Wed 30-Oct-02 15:28 by ealyon

Image text-base: 0x800131D8, data-base: 0x8097D1E8

ROM: System Bootstrap, Version 12.2(8r)YN, RELEASE SOFTWARE (fc1)

ROM: C837 Software (C837-K9O3SY6-M), Version 12.2(8)YN, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

uptime is 1 hour, 8 minutes

System returned to ROM by power-on

System image file is "flash:c837-k9o3sy6-mz.122-8.YN.bin"

CISCO C837 (MPC857DSL) processor (revision 0x200) with 29492K/3276K bytes of memory.

CPU rev number 7

Bridging software.

1 Ethernet/IEEE 802.3 interface(s)

1 ATM network interface(s)

128K bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

2048K bytes of processor board Web flash (Read/Write)

Configuration register is 0x2102

Community Member

Re: NAT translation failed


I have another Cisco 837 with the SAME IOS release and the SAME configuration except adressing information and.. NAT works perfectly.

I restarted the bogous router to be sure the problem isn't caused by any persistent data but it didn't work.


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