The startup configuration can be bypassed by booting into ROMMON or during normal operation. In either case, a reboot is required.

This is particularly useful, for example, if you need to perform a password recovery because you have forgotten your password, or for troubleshooting purposes.

Configuration in IOS

Switch# configure terminal
! to activate
Switch(config)# system ignore startup-config

! to deactivate
Switch(config)# no system ignore startup-config

Configuration in ROMMON

In the background, the IOS command simply sets the ROMMON variable SWITCH_IGNORE_STARTUP_CONFIG to 1 or 0 which we can also do manually.

We had an issue where our domain controller lost its domain network profile after a reboot. When it came back up it was set to public instead of domain.

The problem occurred only when Windows NIC teaming (switch-independent) was used in combination with two network adapters in the team. As soon as one network adapter was disabled from the team (while the other remained active), the network profile (domain) was recognized correctly.