A common issue when running pfSense on generic hardware (DIY builds using standard PC components or virtual machines) is that the serial number field may be blank or read "Default String" or "To Be Filled By O.E.M."

| Method | Steps | |--------|-------| | WebGUI | System > General Setup → Look for “Serial Number” field (read‑only) | | Dashboard | System > Dashboard → System Information widget shows “Serial Number” | | Console / SSH | Run pfSense-upgrade -d or cat /etc/version (some versions) | | Shell command (Unix) | sqlite3 /conf/config.xml "SELECT value FROM system WHERE attribute='serial';" | | Backup file | Inspect /conf/config.xml – search for <serial> tag |

If you purchased an official Netgate appliance (e.g., SG-1100, SG-2100, 6100, 8200, 1541), the serial number is your key to world-class Technical Assistance Center (TAC) support. When opening a support ticket, the first thing Netgate support will ask for is the serial number. This ties your device to your purchase date, warranty status, and support level.

If you cannot access the GUI, you can retrieve the serial via the console or SSH.

For Netgate Appliances (Hardware Serial): Connect to the console (Serial or SSH) and select option 12 (Developer Shell) or 8 (Shell). Run the following command to query the hardware BIOS:

dmidecode -s system-serial-number

Alternatively, on newer Netgate hardware, run:

sysctl -a | grep netgate

(This often reveals the specific Netgate device ID and hardware serial).

For pfSense Plus System ID: From the Shell (Option 8):

cat /etc/pfsense-serial