Serial console via IPMI

When SSH is unavailable (broken network, firewall, boot failure), the serial console redirected by IPMI lets you administer the server as if you were at a KVM screen. Essential on HolyCloud dedicated servers.

Prerequisites

• IPMI/BMC address and credentials from the panel (or delivery email)
• Recent browser or ipmitool / openipmi
• VPN or allowed IP if BMC ACL is restricted
• Java disabled on most browsers — prefer HTML5 SOL (Serial Over LAN)

Web IPMI access

1. HolyCloud panel → server → IPMI / BMC.
2. Open https://IP_BMC/ (self-signed certificate).
3. BMC admin login (often a dedicated user, not Linux root).
4. Menu Remote Control → Console Redirection or iKVM/HTML5.
5. Launch the session; you see BIOS POST then OS boot.

Limit IPMI access to your fixed IP in BMC settings — high attack surface.

Serial console (SOL) with ipmitool

From a Linux workstation or management VPS:

sudo apt install -y ipmitool openssh-client
export BMC_IP=203.0.113.10
export BMC_USER=admin
export BMC_PASS='mot_de_passe_bmc'

# test
ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS chassis status

Enable SOL if needed (vendor-specific) then:

ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS sol activate

To exit: ~. or the sequence documented by the firmware.

Serial redirection in Linux (target)

On Debian, enable serial console for grub and login:

/etc/default/grub:

GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"
GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"

sudo update-grub

Systemd getty on serial:

sudo systemctl enable serial-getty@ttyS0
sudo systemctl start serial-getty@ttyS0

Speed 115200 must match BMC settings (often under Serial Port settings).

Use cases

| Situation | Action via SOL |

|-----------|----------------|

| Rescue boot | Choose GRUB Advanced options entry |

| Blocked fsck | Answer interactive prompts |

| Firewall blocks SSH | Fix ufw or nftables |

| Forgotten root password | Single-user mode / live ISO via virtual media |

Virtual media + serial

Combine virtual ISO (Debian netinst) and console to reinstall without the panel:

1. IPMI → Virtual Media → mount ISO.
2. Boot order CD first.
3. Follow the installer in the HTML5 console.

BMC security

• Change the default BMC password immediately.
• Disable anonymous accounts, public SNMP.
• Update BMC firmware when HolyCloud publishes a recommendation.
• Do not expose the IPMI port on the Internet without a VPN tunnel.

# example: list IPMI users
ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS user list

Troubleshooting

| Problem | Hint |

|----------|-------|

| Black SOL screen | Serial speed, sol activate vs iKVM |

| Session dropped | BMC timeout — increase in settings |

| IPMI unreachable | Management network, ACL, datacenter ticket |

| Garbage characters | Wrong baud rate (9600 vs 115200) |

Best practices

• Test the console before a major network migration.
• Document BMC IP and procedure for the team (password vault).
• After intervention, sol deactivate and close the web session.

Need help?

HolyCloud can reset BMC access, verify management port connectivity, or replace a motherboard if SOL is hardware-faulty.