Cisco Secure Firewall Management Center Virtual Getting Started Guide

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Prepare the Day 0 Configuration File

Updated: February 5, 2026

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Overview

Learn how to create and apply a Day 0 configuration file to automate the initial setup of Management Center Virtual. Understand how to configure host name, administrator password, network settings, and how to convert the file to an ISO file and attach it for use at first boot.

You can prepare a Day 0 configuration file before you launch the Firewall Management Center Virtual. The Day 0 configuration is a text file that contains the initial configuration data that gets applied at the time a virtual machine is deployed. This initial configuration is placed into a text file named “day0-config” in a working directory you chose, and is manipulated into a day0.iso file that is mounted and read on first boot.

Note

The day0.iso file must be available during first boot.

If you deploy with a Day 0 configuration file, the process allows you to perform the entire initial setup for the Firewall Management Center Virtual appliance. You can specify:

  • EULA acceptance

  • A host name for the system

  • A new administrator password for the admin account

  • Network settings that allow the appliance to communicate on your management network If you deploy without a Day 0 configuration file, you must configure System-required settings after launch; see Deploy Without Using the Day 0 Configuration File for more information.

    Note

    We use Linux in this example, but there are similar utilities for Windows.

  • Leave both DNS entries empty to use the default Cisco Umbrella DNS servers. To operate in a non-DNS environment, set both entries to “None” (not case sensitive).

Procedure

1.

Enter the CLI configuration for the Firewall Management Center Virtual network settings in a text file called “day0-config”.

Example:


#FMC
{
    "EULA": "accept",
    "Hostname": "FMC-Production",
    "AdminPassword": "r2M$9^Uk69##",
    "DNS1": "10.1.1.5",
    "DNS2": "192.168.1.67",
    
    "IPv4Mode": "manual",
    "IPv4Addr": "10.12.129.45",
    "IPv4Mask": "255.255.0.0",
    "IPv4Gw": "10.12.0.1",
    "IPv6Mode": "enabled",
    "IPv6Addr": "2001:db8::a111:b221:1:abca/96",
    "IPv6Mask": "",
    "IPv6Gw": "",
}
2.

Generate the virtual CD-ROM by converting the text file to an ISO file:

Example:


/usr/bin/genisoimage -r -o day0.iso day0-config

or

Example:


/usr/bin/mkisofs -r -o day0.iso day0-config
3.

Repeat to create unique default configuration files for each Firewall Management Center Virtual you want to deploy.

What to do next

  • If using virt-install, add the following line to the virt-install command:

    --disk path=/home/user/day0.iso,format=iso,device=cdrom \

  • If using virt-manager, you can create a virtual CD-ROM using the virt-manager GUI; see Deploy the Firewall Management Center Virtual.