read only flash

[mugwuffin]

apart from 2500's can any other routers flash be made read-only? (mainly interested in 26xx, 17xx, 3640's) preferably by some undocumented command as opposed to jumpers or dodgy soldering, etc.. ?

if not, why does the command 'show flash' report "(Read/Write)" at the end?

 

[jamin123]

What is your config-reg setting?

 

[tschouten]

Because Flash is an EPROMM chip, this allows you to write to it under certain circumstances. As you already know it reads from it at every boot. In order to block access to this you enable the secret, or use AAA along with other forms of security access much llike you would for any OS admin account.

It all depends on the level of access someone has to the router. You can also disable the password recovery access (known as sending the control break during boot-up first 60 seconds) to the router, though this isn't safe (oe recommended) unless you REALLLLLY know what you are doing. It takes a lot of work to get your router back if you mess up on that one, but it can be done. Truly there is no need to do this when you can jnust control someones access to the console port (aka lock the device in a secure area.)