Cisco Certified Network Professional 2025 – 400 Free Practice Questions to Pass the Exam

In a VTP (VLAN Trunking Protocol) environment, the VLAN database is stored in the "vlan.dat" file. This file plays a crucial role in maintaining the information about the VLANs configured on the switch. When a switch operates in a VTP domain, it uses this file to store the details for all VLANs (including their IDs, names, and associated parameters). The "vlan.dat" file is typically located in the flash memory of the switch, allowing it to persist across reboots.

This method of storage is essential for consistency in VLAN configurations across multiple switches within the same VTP domain, as switches communicate with each other and propagate VLAN information. Other storage options such as the running-config or startup-config files do not contain VLAN information in a VTP environment, as these files are primarily used for other configurations and do not facilitate the management of VLANs in the way that "vlan.dat" does.