The IBM Baseboard Management Controller (BMC) operates independently from the host system with its own processor, memory, and network interface. This separation allows for management operations even when the main server is powered off or unresponsive.

Here are three reliable approaches to restart the BMC while keeping your server running:

1. Using IPMI Commands

# First check BMC status
ipmitool -H [BMC_IP] -U [username] -P [password] mc info

# Soft reset the BMC (recommended first attempt)
ipmitool -H [BMC_IP] -U [username] -P [password] mc reset warm

# If soft reset fails, try cold reset (more forceful)
ipmitool -H [BMC_IP] -U [username] -P [password] mc reset cold

2. Physical Reset Methods

For IBM System x and Power Systems:

• Locate the BMC reset jumper (consult your hardware manual)
• Alternatively, find the small circular BMC reset button (typically requires a paperclip)
• For newer models, press and hold the ID button for 10 seconds

3. SNMP-Based Reset (when web interface is down)

# Example using net-snmp tools
snmpset -v 2c -c [community_string] [BMC_IP] .1.3.6.1.4.1.2.3.51.3.1.1.0 i 1

• BMC reset typically takes 1-3 minutes to complete
• Active management sessions will be terminated
• Custom BMC settings may revert to defaults
• Always verify network connectivity after reset with:

ping [BMC_IP]

If standard methods fail, try this advanced sequence:

1. Check for firmware updates: ipmitool -H [BMC_IP] -U [username] -P [password] mc info | grep 'Firmware Revision'
2. Attempt BMC firmware recovery mode
3. As last resort, perform managed host reboot (loses server uptime)

Document your BMC reset procedures for future reference, noting any model-specific behaviors you encounter during the process.

The IBM Baseboard Management Controller (BMC) operates as an autonomous subsystem with its own dedicated processor, memory, and network interface. This architectural separation enables administrators to perform management operations independent of the host server's power state.

Option 1: IPMI Command Line Reset

ipmitool -I lanplus -H  -U  -P  mc reset cold
# Alternative warm reset (preserves some settings)
ipmitool -I lanplus -H  -U  -P  mc reset warm

Option 2: Physical Reset via Service Processor

On IBM System x and Power servers, locate the dedicated BMC reset jumper (typically labeled "CLR_CMOS" or "BMC_RST"). Short pins 1-2 for 5 seconds while host power remains connected.

For servers with non-responsive web interfaces but functional SNMP:

snmpset -v 2c -c   \
1.3.6.1.4.1.2.3.51.3.3.1.1.0 i 6
# IBM-specific OID for BMC reset

#!/bin/bash
BMC_IP="192.168.1.100"
CREDS="ADMIN:ADMIN"

# First attempt IPMI reset
if ipmitool -I lanplus -H $BMC_IP -U ${CREDS%:*} -P ${CREDS#*:} mc info; then
    ipmitool -I lanplus -H $BMC_IP -U ${CREDS%:*} -P ${CREDS#*:} mc reset cold
else
    # Fallback to SNMP
    snmpset -v 2c -c public $BMC_IP 1.3.6.1.4.1.2.3.51.3.3.1.1.0 i 6
fi

After reset, monitor BMC availability with:

ping -c 4 
ipmitool -I lanplus -H  -U  -P  mc info
# Expected output includes "Firmware Revision" and operational status

• Allow 3-5 minutes for BMC to fully initialize after reset
• Persistent failures may require firmware update via IMM2 web interface
• For xClarity Controller systems, use dedicated LC commands