Default configuration parameters

[kapishmohole.cisco]

'Show run' don't show default configuration parameters, interface specific default parameters. It only shows manually entered commands only.

Is there any way to find out default all hidden configuration commands and values?

[tepatel]

No..there is no straight way to find the default values for different parameters and commands.

[Just Someone YKnow]

It's been seven years since someone else asked this question, so I'm looking for an update.

We just bought a UC560, mainly intending it as our new VoIP phone controller:

Cisco IOS Software, UC500 Software (UC500-ADVIPSERVICESK9-M),  Version 15.0(1)XA2, RELEASE SOFTWARE (fc2)
Compiled Sat 06-Mar-10 04:52 by prod_rel_team

ROM: System  Bootstrap, Version 15.0(1r)XA, RELEASE SOFTWARE (fc1)

Apparently it can also do routing, NAT, DHCP, and a basic firewall. I wasn't planning to use it for that, and was planning to migrate from Netware 6.5 routing/firewall to Microsoft RRAS, but I guess if this Cisco box can do it, might as well.

But I am not (yet?) a Cisco certified tech so I don't have the 1000 command line options and defaults all memorized.

If I enable DHCP, can it tell me the default address lease time? Does the Cisco DHCP ping addresses before assigning them, to avoid accidental overlaps? "show running_config" only shows what we have configured, not what the any of the defaults are..

[hoses]

And what about parameters with default values in our self-developed services?

We developed a package where a leaf (let's call it leaf1) in YANG has a when statement depending on another leaf (leaf2) and a default statement. When the when condition is met, our leaf1 will have the default value assigned, but it won't be visible via Restconf API or "show running-config". If we navigate the Magic node then we can see that value there, or whenever we use the leaf in the python code.

While this behavior of hiding default values is common on network devices to avoid showing all default values and only show what is specifically configured, it causes misunderstandings during service development.

[katrin1701]

I found

show run all

very helpful.

[Joseph W. Doherty]

Indeed, "show run all" can be helpful, but it alone doesn't alone show hidden defaults.

That might be accomplished by first booting without a startup config.  "Show run all" should then show defaults, but to highlight the commands that are hidden, perform a diff between "show run" and "show run all".

BTW, what actual default will be and/or what's hidden, can vary across IOSs (and installed hardware).

[katrin1701]

Only yesterday I had to use the command

default ...

because I couldn't get rid of a configuration line with no ...

I had forgotten the command default exists at all.

I also like

show archive config differences

so you know what you haven't saved yet

[Joseph W. Doherty]

Re: default command.  Yup, can be very handy, especially used with a range command to "reset" a set of ports.  I've also bump into the issue you've mentioned.

Re: show archive conf differences.  Laugh, just very recently, in another thread, mentioned how useful I've found that command, not only for a confirmation of what I've changed before I do a save, but also checking whether there are any pending unsaved changes before I start making my changes.