The SuperMicro X8SIE-F motherboard comes with three distinct network interfaces:

• LAN1: Primary gigabit Ethernet port (Intel 82574L)
• LAN2: Secondary gigabit Ethernet port (Intel 82574L)
• IPMI_LAN: Dedicated BMC port (Realtek RTL8201N)

There are several practical reasons for configuring IPMI to use a shared LAN port:

1. Reduced physical port requirements in rack environments
2. Better utilization of higher-quality Intel NICs
3. Avoidance of the slower dedicated Realtek IPMI port
4. Simplified network cabling in space-constrained setups

Follow these steps to enable shared LAN mode:

1. Enter BIOS setup (DEL during boot)
2. Navigate to "Advanced -> PCIe/PCI/PnP Configuration"
3. Set "Onboard LAN1 Option ROM" to Enabled
4. Go to "IPMI Configuration"
5. Change "Share LAN" from Disabled to LAN1 or LAN2
6. Save changes and reboot

After reboot, check the IPMI network settings:

ipmitool lan print 1

Sample output for shared mode:

IP Address Source       : Static
IP Address              : 192.168.1.100
MAC Address             : 00:25:90:xx:xx:xx (matches LAN1 MAC)
Subnet Mask             : 255.255.255.0
Default Gateway IP      : 192.168.1.1

Problem: IPMI becomes inaccessible after sharing

Solution: Reset BMC configuration by:

ipmitool bmc reset cold

Problem: Network performance degradation

Solution: Configure VLAN tagging:

ipmitool lan set 1 vlan id 100

Here's a bash script to configure shared LAN mode:

#!/bin/bash
# Enable LAN1 shared mode
ipmitool raw 0x30 0x70 0x0c 0x00 0x00 0x01

# Set static IP (replace with your values)
ipmitool lan set 1 ipsrc static
ipmitool lan set 1 ipaddr 192.168.1.100
ipmitool lan set 1 netmask 255.255.255.0
ipmitool lan set 1 defgw ipaddr 192.168.1.1

# Reset BMC to apply changes
ipmitool bmc reset cold

When using shared LAN mode, keep in mind:

• IPMI traffic shares bandwidth with host network traffic
• Network throughput may decrease during heavy BMC operations
• For critical environments, consider using VLAN separation
• Latency-sensitive applications may prefer the dedicated port

For older firmware versions that don't support BIOS configuration:

# Direct register modification
ipmitool raw 0x30 0x70 0x0c 0x00 0x00 0x01

This writes directly to the BMC register to enable sharing.

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The SuperMicro X8SIE-F motherboard comes with three distinct network interfaces:

• LAN1: Primary OS network interface (Intel 82574L)
• LAN2: Secondary OS network interface (Intel 82574L)
• IPMI_LAN: Dedicated BMC interface (Realtek RTL8201N)

There are several practical reasons for configuring IPMI to use a main LAN port:

1. Physical port limitation in 1U chassis
2. Need for redundant IPMI access
3. VLAN segmentation requirements
4. Avoiding dedicated IPMI switch ports

Access your BMC web interface (default IP: 192.168.1.100) and navigate to:

Configuration → Network → IPMI over LAN

Set these parameters:

Channel Number: 1 (for LAN1) or 2 (for LAN2)
Shared LAN: Enabled
VLAN ID: Optional (if using VLAN tagging)

Reboot and enter BIOS (DEL key during POST):

Advanced → IPMI Configuration → 
Set "Share LAN Port" to Enabled
Select "LAN1" or "LAN2" as shared port

After applying changes, verify with ipmitool:

ipmitool -I lanplus -H [BMC_IP] -U admin -P admin channel info 1
ipmitool -I lanplus -H [BMC_IP] -U admin -P admin lan print 1

Look for "Shared" status in the output.

For a Linux host with VLAN segmentation:

# Create VLAN interface for IPMI
ip link add link eth0 name eth0.100 type vlan id 100
ip addr add 192.168.100.2/24 dev eth0.100
ip link set eth0.100 up

# Configure persistent IPMI VLAN
echo "options igb VLAN=100" > /etc/modprobe.d/igb.conf

• Ensure switch port is configured as trunk if using VLANs
• Check for IP conflicts between OS and BMC interfaces
• Update to latest BIOS and BMC firmware if issues persist
• Test with direct cable connection before complex network setups

When sharing interfaces:

- Always use dedicated VLAN for IPMI traffic
- Change default credentials immediately
- Enable encryption (IPMI 2.0 required)
- Restrict access via firewall rules