Server Serial-Over-LAN (SOL) Configuration and Access

This guide outlines the prerequisites and steps for establishing a connection to a server’s serial console using IPMI’s Serial-Over-LAN.

Prerequisites and Configuration

To ensure SOL connectivity, the following components must be correctly configured:

  1. BIOS Configuration:

    1. Enable the serial port;

    2. Set the appropriate baud rate (typically defaults to 115200n8);

    3. Enable Serial Console Redirection.

  2. GRUB Settings Configuration (for OS Output):

    1. Edit the GRUB configuration file (/etc/default/grub);

      1. Add the kernel parameter console=ttyS0,115200n8;

        Note

        The serial console baud rate must match the BIOS setting. A mismatch will prevent GRUB and OS output from appearing after the POST screen.

      2. Remove the quiet kernel parameter if present.

    2. Update GRUB:

      1. Debian-based: sudo update-grub2

      2. RHEL-based: sudo grub2-mkconfig -o <GRUB BOOT CONF>

  3. IPMI/BMC Serial Console Settings:

    1. Verify and update the Serial-Over-LAN settings within the server’s IPMI/BMC interface (iLO for HPE, iDRAC for Dell).

      1. HPE ProLiant: https://support.hpe.com/hpesc/public/docDisplay?docId=sd00001038en_us&page=GUID-D7147C7F-2016-0901-06D0-000000001FE3.html&docLocale=en_US

      2. Dell PowerEdge: https://www.dell.com/support/kbdoc/en-us/000224291/how-to-use-the-serial-over-lan-on-the-idrac

Confirm IPMI Availability

  1. Check the IPMI Management IP:

    ipmitool lan print // Check for the "IP Address" field

  2. Verify Reachability:

    Check that the IPMI management IP is reachable from the node that will initiate the SOL connection.

    ping -c3 <IPMI_management_IP>

Connecting to the Serial-Over-LAN Console

Initiate the SOL session:

ipmitool -I lanplus -H <IPMI_management_IP> -U <user> -P <pass> sol activate

Note

If the connection fails due to a cipher suite mismatch with the IPMI module, force a specific cipher suite using the -C flag (e.g., -C3).

ipmitool -I lanplus -H <IPMI_management_IP> -U <user> -P <pass> -C3 sol activate

Once connected, a serial terminal session is established, allowing console access. The POST output should appear first, then GRUB and the operating system messages.

To terminate the serial console session, use the IPMI escape sequence: ~~.. The IPMI module will intercept this sequence and close the SOL connection.

For detailed information on adjusting kdump settings and modifying GRUB kernel parameters, please check Adjusting kdump settings and GRUB kernel parameters.