F5 BIG-IP i2800 Password Recovery

Step-by-step password recovery for the F5 BIG-IP i2800 (BIG-IP iSeries (TMOS)). Console access required.

Overview

This guide provides step-by-step instructions for resetting lost or forgotten administrative passwords on enterprise networking hardware. Follow the procedure below carefully to regain access while preserving your device configuration.

Prerequisites

Before proceeding with password recovery, ensure you have a console cable, terminal emulation software configured to 9600 baud, and physical access to the device.

Step 1: Establish Console Connection

Connect your terminal cable to the console port of the device and open your serial terminal session.

Step 2: Interrupt the Boot Sequence

Power cycle the hardware and issue a Break key sequence during initial system startup to enter ROMMON mode.

Step 3: Reset Password & Configuration

Bypass startup configuration loading, boot into system software, set your new credentials, and save changes back to non-volatile memory.

Overview

This procedure recovers administrator access to the F5 BIG-IP I2800 running F5 BIG-IP when the root/admin password is lost. BIG-IP's GRUB boot loader supports single-user mode, which drops to a root shell where the passwords can be reset — the configuration is preserved.

Prerequisites

Console cable (RJ-45 serial on most BIG-IP hardware) with a terminal session at 9600 baud, 8N1 (older platforms) or 115200 baud (iSeries/rSeries — check the model's guide). Physical or remote power access to reboot the appliance.

Recovery Procedure — GRUB Single-User Mode

Connect the console cable with the correct baud rate and open a terminal session.
Reboot the appliance (power-cycle or reboot if you have access).
When the GRUB boot menu appears, press a key to stop the auto-boot countdown.
Select the BIG-IP boot entry and press e to edit it.
Find the kernel line (starting with linux or kernel) and append single to the end.
Press Ctrl+X (or F10) to boot with the modified entry. The appliance drops to a root shell.
Mount the root filesystem read-write: mount -o remount,rw /
Reset the root password: passwd root — enter the new password twice.
Reset the admin user password (the F5 web/UI admin): passwd admin.
Reboot: reboot. Log in as root (SSH/console) or admin (web UI) with the new passwords.

Important Notes

Single-user mode preserves the configuration — only the passwords are reset.
Baud rate: BIG-IP 2000–7000 series use 9600; iSeries (i2000–i10800) and rSeries use 115200. Verify the model's console baud before connecting.
F5 has two admin accounts: root (CLI/SSH) and admin (web UI). Reset both if both were lost.
If GRUB is password-protected (F5 allows a GRUB password), the single-user method is blocked — contact F5 support with proof of ownership.
On virtual editions (VE), use the hypervisor console instead of serial.

Protecting Your Configuration

Before recovery, back up the BIG-IP config: via the web UI (System → Archives) or tmsh save sys ucs /var/tmp/backup.ucs. After recovery, restore the UCS archive if needed.