Edit Env_Vars

Is it possible to directly edit the Env_Vars file using IOS? Is it possible to drop from IOS into the underlying linux kernel?

Reply to
Loading thread data ...

You don't say what platform this is, but env_vars filename tends to point me to a small-to-mid range switch platform (ie. 2960).

You can't generally edit files inside IOS, if they aren't protected, you can copy things around after you edit them externally. I don't really desire to try to trash my switches with overwriting system files though, so I'd let you try something like

copy ftp://host/env_vars flash:env_vars

yourself though. Don't know what you hope to gain by doing anything of the sort. If this is to attempt to bypass some sort of licensing, I'm sure cisco would protect any sensative files, or hold the info elsewhere (ie. cookie PROM?) that is not going to be easily touchable, or viewable.

Generally, things running the OS known as IOS aren't running linux, so there's no way into something that doesn't exist. The command shell that you get is the only physical interaction you get with the OS.

Even on the cisco devices that do happen to run linux kernel (ie. NX-OS), the command shell again is the only interaction with the OS. I assume you are thinking of running bash or some other type of shell, and that isn't going to happen.

Reply to
Doug McIntyre

Doug, Thanks for the informative reply.

I'm working with a 1231 AP. I had addressed the BVI1 interface as as a temporary work-around while DHCP was down. Now after rebooting the AP, DHCP gives it a valid lease but the AP releases it around 15 seconds later and it goes back to Since I see it in env_vars, I figured I'd delete this file but even after doing so, erasing the startup file and reloading, the value of this variable was restored in the new Env_vars file. Can you tell me where this info is stored?
Reply to

snipped-for-privacy@yahoo.com schrieb:

A safe and supported/documented way is - to reset the AP using the mode button - to reset via the web interface and then a complete reconfigure.

If you update the configuration of interface BVI1 and then store the configuration, the addresses in env_var should be updated to the new config.

Reply to
Uli Link

I reset and downloaded a fresh copy of IOS from tftp at This solved the problem but in a very inefficient manner. I had hoped to learn a bit more about where this variable is stored across reboots when neither env_vars nor the startup config are present.

Reply to

on an aIOS AP, flash:env_vars (i.e. the bootloader variables) and nvram:startup-config are pretty much the whole of the config. Don't know why your IP address came back.

The most elegant way of cleaning out the static IP address info from env_vars is:

ap#write default-config

This restores not only the startup-config but also env_vars to the defaults.



Reply to
Aaron Leonard

THANKS! This is exactly what I was looking for. I look forward to trying this out next week. Bob

Reply to

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.