Disable IP Routing

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Overall Rating: 5 (1 ratings)
ankbhasi Wed, 04/25/2007 - 23:01

Hi Peter,

Just want to confirm if you have configured the switch to pick the config from network somehwhere when switch boot or its picks from nvram? Also can you paste the output of "sh version"?



Hi Ankur,

The switch is booted up from NVRAM. Below is the output of sh version and show boot.

XAP-ACCESS-1A>sh ver

Cisco Internetwork Operating System Software

IOS (tm) s3223_rp Software (s3223_rp-IPSERVICESK9_WAN-M), Version 12.2(18)SXF6,


Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2006 by cisco Systems, Inc.

Compiled Mon 18-Sep-06 18:56 by tinhuang

Image text-base: 0x40101040, data-base: 0x42D28000

ROM: System Bootstrap, Version 12.2(17r)SX3, RELEASE SOFTWARE (fc1)

BOOTLDR: s3223_rp Software (s3223_rp-IPSERVICESK9_WAN-M), Version 12.2(18)SXF6,


XAP-ACCESS-1A uptime is 4 hours, 38 minutes

Time since XAP-ACCESS-1A switched to active is 4 hours, 37 minutes

System returned to ROM by power cycle (SP by power on)

System image file is "sup-bootdisk:s3223-ipservicesk9_wan-mz.122-18.SXF6.bin"

cisco WS-C6513 (R7000) processor (revision 1.1) with 458752K/65536K bytes of mem


Processor board ID SAL104574H8

R7000 CPU at 300Mhz, Implementation 0x27, Rev 3.3, 256KB L2, 1024KB L3 Cache

Last reset from power-on

SuperLAT software (copyright 1990 by Meridian Technology Corp).

X.25 software, Version 3.0.0.

Bridging software.

TN3270 Emulation software.

2 Virtual Ethernet/IEEE 802.3 interfaces

153 Gigabit Ethernet/IEEE 802.3 interfaces

1915K bytes of non-volatile configuration memory.

65536K bytes of Flash internal SIMM (Sector size 512K).

Configuration register is 0x2102

XAP-ACCESS-1A>sh boot

BOOT variable = sup-bootdisk:,1;

CONFIG_FILE variable =

BOOTLDR variable does not exist

Configuration register is 0x2102

Richard Burts Thu, 04/26/2007 - 03:17


Ankur's question investigates the possibility that the 6513 is set to ignore the NVRAM config. And your response shows that the config register is set to 2102 which will read the config file in NVRAM at bootup.

So I am wondering if there is some issue with copying running config to startup config. After you make the change and copy the config file, if you do show startup-config do you find the no ip routing command in the config file? As a way to investigate this, I wonder if you change something else in the config (add/change a description on an interface for example) if that survives a reboot and is still in the config.



Richard Burts Thu, 04/26/2007 - 03:55


Am I understanding correctly that you have entered the no ip routing command, that the behavior of the 6513 has changed, but that the command does not show up in the running config? That is very wierd. I think the next step is probably to open a case with TAC, because this sounds very buggy to me.



Amit Singh Thu, 04/26/2007 - 03:56


This switch reaction of not saving the config is because the option to remove the default

state of "ip routing"is not supported on the catalyst 6500 switches running IOS

The "no ip routing" command is not intended to be used on the Cat6K.

"no ip routing" is a classical IOS command which is to disable IP routing on routers. This command is usually used on low-end routers, on cat6k this command doesn't make sense and should be blocked. However, this command is useful for some internal testing, so the decision is to make it internal for cat6k only. As a result of this change , command will not be saved across reload if entered.


-amit singh

Richard Burts Thu, 04/26/2007 - 04:34


This is a very interesting find. Good for you. My rating is well deserved.


No need for TAC. While I am not sure that I agree that it makes no sense on cat6k, the link that Amit provides clearly shows that this is an intentional behavior and not a bug.




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