IP CLASSLESS not working

There are numerous commands that do not show up in the configuration file when set to their default state. Furthermore, the default may change from one IOS release to another, as well as whether they show up when configured to their default state.

The behavior of "Default Routing" is very much dependent on the setting of "IP Classless", and is likely the functional issue you have observed.

Best Regards, News Reader

On by default.To prove it, try "no ip classless" and watch that appear.

AFAIK these commands are a special case of what is displayed by show running-config; typically default commands are not displayed.

Both of the commands "ip classless" and "no ip classless" will show up in output of sh running-config.

At least this is the behavior with IOS 12.3

Hi Max,

Somewhere around IOS V12.0 the DEFAULT for alI versions of IOS was changed from CLASSFULL to CLASSLESS. As the DEFAULT does not always show up, this may explain why it appears to be not working.

If your Router is in CLASSFULL mode, then you would not be able to configure a Subnetted mask on any command that needed it. If you CAN configure it, then its in CLASSLESS mode.

Cheers.......................pk.

Please post output of show version from the 871W

Thanks everyone! I thought that would be the problem why some program aren't working through the VPN, but then i guess it's not... i'll have to look somewhere else. It's because it's mainly the only difference i could find in the 2 configs... thanks a lot for yout help!!

You may have a defective 12.4 image on the 871W.

Post the output of show version

Are you abandoning pursuit of the theory because the state of the "ip classless" command is not displayed the way you expected, or because you have confirmed that there is no behavioral change resulting from the removal of "no ip classless" (by entering "ip classless")?

I'm confused by your conclusion.

Your initial post stated:

But you can enable IP Classless; it just may not show up as you expected (the "no ip classless" will disappear).

Change anything in terms of seeing the command as you expected, or change anything in terms of a resolution to the VPN issues when "no ip classless" has been removed (by entering "ip classless")?

When "no ip classless" has been removed by entering "ip classless", is there a change in the VPN behavior?

Depending on your addressing scheme, "no ip classless" could cause undesired behavior due to its impact on "Default Routing".

Best Regards, News Reader

~ AFAIK these commands are a special case of what is displayed by show ~ running-config; typically default commands are not displayed. ~ ~ Both of the commands "ip classless" and "no ip classless" will show up ~ in output of sh running-config. ~ ~ At least this is the behavior with IOS 12.3

Ordinarily the default state of a command is not shown in the config ("NVGEN'd".)

However, an exception is made when we change a command's default. What is supposed to happen there, is this:

First, we start NVGEN'ing the old behavior.

Then, some time later, we switch to the new behavior, and NVGEN both the old and new behavior.

Then, we stop NVGEN'ing the new behavior.

The idea is to make it apparent that the defaults are changing.

Aaron

NVGEN?

It would be helpful for your audience if you specified what your acronym stood for.

Best Regards, News Reader

from CCO

" Cisco IOS Software Configuration Storage

In the Cisco IOS software configuration model, the configuration state is maintained in a distributed manner, with each component storing its own configuration state. To retrieve configuration information, the software must poll every component to collect the distributed information. This configuration state retrieval operation is performed by a process known as nonvolatile generation (NVGEN), and it is used by command line interpreter (CLI) commands such as show running- configuration, write memory, and copy system:running-configuration to display or copy the running system configuration. When invoked, NVGEN queries each system component and each instance of interface or other configuration objects. A running configuration file is constructed as NVGEN traverses the system performing these queries.

Thank you Merv.

Best Regards, News Reader

To make this a bit clearer perhaps:

When a command is "NVGEN'd", its state is written ("GENerated", I guess) to nonvolatile (NV) memory.

That explains why it takes so much CPU for a sh run, wr mem.

This has puzzled me for some time. "... what is it /doing/ ????"

Thanks.

By the way at least some platforms (maybe 4500/6500) have a way of displaing the defaults config "entries" if required.

sh run include-default ! - sort of thing - I just made the keyword up.

show running-config all

To display the entire operating configuration, including defaults, that is running on the security appliance, use the show running-config all command in privileged EXEC mode.

It is buidlinbg a text version of the internal running-config

compare what happens with the tow commands

show startup-config

notice that the config is displayed immediately - this is because it is stored as a text file

versus

show running-config

NOTICE the "Building configuration ..." message

This would lead me to conclude that the running-config is not stored as a text file and that iit needs to be created dynamically each time the show run command is entered