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2851 how many nat translations support


I have a 2851 and i just want to know how many ip nat translations can this router support. Currently i have a issue with some ip addresses making a several number of ip nat translations, and the cpu utilization get up to 99%.

Hall of Fame Super Gold

Re: 2851 how many nat translations support

Which exact IOS are you running? There have been bugs like that in the past.

New Member

Re: 2851 how many nat translations support

Cisco IOS Software, 2800 Software (C2800NM-ADVENTERPRISEK9-M), Version 12.4(20)YA2, RELEASE SOFTWARE


Technical Support:

Copyright (c) 1986-2009 by Cisco Systems, Inc.

Compiled Thu 22-Jan-09 15:17 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

2851-ROUTER uptime is 3 hours, 39 minutes

System returned to ROM by reload at 07:26:09 CENTRAL Thu Mar 5 2009

System image file is "flash:/c2800nm-adventerprisek9-mz.124-20.YA2.bin"

This product contains cryptographic features and is subject to United

States and local country laws governing import, export, transfer and

use. Delivery of Cisco cryptographic products does not imply

third-party authority to import, export, distribute or use encryption.

Importers, exporters, distributors and users are responsible for

compliance with U.S. and local country laws. By using this product you

agree to comply with applicable laws and regulations. If you are unable

to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:

If you require further assistance please contact us by sending email to

Cisco 2851 (revision 53.51) with 247808K/14336K bytes of memory.

Processor board ID FTX1227A3KF

3 Gigabit Ethernet interfaces

1 Virtual Private Network (VPN) Module

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2103

Re: 2851 how many nat translations support

It looks like NAT translations are limited by the about of DRAM in IOS, see the link below :-


Take a look at what is eating the CPU with the command

show process cpu sorted

Or as mentioned above, it could be a bug

New Member

Re: 2851 how many nat translations support

Like i said before:

179 3453980 58910 58631 93.30% 92.12% 92.50% 0 IP NAT Ager

Hall of Fame Super Gold

Re: 2851 how many nat translations support

Do you need YA for any reason ? Can you try 12.3(3j) instead ?

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