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                            Duncan Laurie

ipmitool is a utility for managing and configuring devices that support
the Intelligent Platform Management Interface.  IPMI is an open standard
for monitoring, logging, recovery, inventory, and control of hardware
that is implemented independent of the main CPU, BIOS, and OS.  The
service processor (or Baseboard Management Controller, BMC) is the brain
behind platform management and its primary purpose is to handle the
autonomous sensor monitoring and event logging features.

The ipmitool program provides a simple command-line interface to this BMC.
It features the ability to read the sensor data repository (SDR) and print
sensor values, display the contents of the System Event Log (SEL), print
Field Replaceable Unit (FRU) inventory information, read and set LAN
configuration parameters, and perform remote chassis power control.

I originally wrote ipmitool while between projects and employeed at Sun
Microsystems.  Sun had just embarked on a new line of general-purpose x86
servers that included an OEM Intel board with an IPMIv1.5 BMC on board.
It started with an idea that remote chassis power control would be a handy
feature for my systems in the lab and from there it grew into a multi-
purpose tool that lots of people found useful.  I decided to release it
under a BSD license and give others the chance to make use of it.

ipmitool was not written to provide large-scale (aka Enterprise) management
application functionality.  The functionality that ipmitool proivides is
easily accomplished by sending simple IPMI request messages and parsing
the returned response.  It is intended to be used by system administrators
who like the simplicity and scriptability of command-line utilities, as
well as those debugging or developing their own BMC implementations.

Obviously the largest requirement is hardware with a service processor
that supports the IPMI specification.  Many x86-based servers are now
coming with IPMI support, check with your preferred hardware vendor
about available products.

Once you are certain you have the required hardware, you then need to
decide how you want to access the BMC.  The most common case involve
access through the System Interface or over the LAN.  (or serial, but
currently ipmitool does not support the serial interface)

System Interface
There are multiple types of system interfaces, but they are all similar
enough to allow a single well-designed driver to support them all.  
Different types of system interfaces include Keyboard Controller Style
(KCS), Block Transfer (BT), System Management Interface Chip (SMIC) and
SMBus.  Different hardware vendors will have different preference and

On Linux the OpenIPMI kernel driver should support all of these system
interfaces and it should be a simple matter of loading the right
kernel modules and setting up the device node to use it.  The driver
module names vary slightly in different kernel versions, but for all
releases you need these two modules:

  ipmi_msghandler: incoming and outgoing message handler
  ipmi_devintf: character device interface to IPMI driver

For 2.4.x and early 2.6.x kernels you need to choose a module based on
the type of system interface your hardware supports.  For example:

  ipmi_kcs_drv: Keyboard Controller Style driver

More recent 2.6.x kernels have combined these into a single module:

  ipmi_si: a universal IPMI system interface driver

See the documentation that comes with your distribution and/or kernel
for more information on what kernel modules are required.  Once the
required modules are loaded and the driver has found a suitable system
interface to the BMC then you need to ensure the device node at
/dev/ipmi0 is pointing at the correct major number.

This is because OpenIPMI is given a dynamically assigned major number
when it is loaded, but depending on what other modules are present
this number may be anywhere from 254 on down.  The easiest way to tell
is to check the output of /proc/devices and see what major number the
"ipmidev" device is assigned to.

There is a sample script included with ipmitool called ipmi.init that
can be used to automate this process at bootup.

LAN Interface
This is often referred to as "IPMI-over-LAN" and defines how IPMI messages
can be sent to and from the BMC encapsulated in Remote Management Control
Protocol (RMCP) packets which are then transferred as UDP datagrams.

IPMI-over-LAN is only supported with version 1.5 and higher of the IPMI
specification.  The RMCP packet format is defined by the Alert Standard
Forum, and it has been followed up with the RMCP+ protocol that adds
encryption and payload support.  The IPMIv2 specification was updated
accordingly to to support the RMCP+ protocol and brings with it enhanced
security with encryption as well as support for Serial over LAN.

There are different types of LAN interfaces as well.  Some systems have
shared management networks where the NIC will intercept UDP packets to
port 623 and redirect them to the BMC over SMBUS.  This type of LAN
interface requires that the BMC be configured with the same settings that
the system uses.  It also suffers from an increased security risk just by
the nature of sharing that interface with normal traffic.

I have also seen bugs in some implementations that have rendered the
IPMI-over-LAN feature "dangerous" to enable in some situations.  (in
particular there can be an issue with RPC because it will sometimes choose
to use port 623 and you will lose response packets...)

There is a sample shell script included with ipmitool called bmclanconf
that can be used to simplify the LAN settings configuration process using
the System Interface to configure the settings.  In some cases the
hardware will come with a utility (often a DOS bootable CD) for configuring
enabling the LAN interface as well.

In order to support the IPMIv2.0 interface you must have an OpenSSL library
with the required encryption functions.  Recent distributions should have
no problems.  The IPMIv1.5 interface will attempt to use OpenSSL for MD5
hash function at compile time but if that is not found it will use an
internal library.

IPMB Dual Bridging in  IPMITOOL

IPMI offers a standard messaging interface.

The following concepts are related to this messaging interface:

Channel type     : Communication channel type (SMS/KCS, IPMB, LAN) 
Channel number   : Channel descriptor
Requester        : Address of the requester
Responder        : Address of the responder
NetFN            : The logical function  for the request/response.
Command          : The command number 
Sequence         : An ID identifiying the request/response pair
Message tracking : The ability to match request/response pair.

When a communication is issued through any of the channels, an application 
formats a request and expect a response. 

Direct Command
The simplest form of communication is a "direct command" using SMS/KCS

 ipmitool raw 6 4
  55 00

This send raw command 4 (selftest) from netfn 6(application) to KCS, the driver 
takes care of 'message tracking' and provides the answer.

Hopefully, the application also includes a "human readable" instance of the API:
 ipmitool mc selftest
 Selftest: passed

Bridged Command
One slightly more complicated communication mode is the so-called 
"bridged command" using IPMB. 

 ipmitool -m 0x94 -t 0x9a raw 6 4
 55 00
 ipmitool -m 0x94 -t 0x9a mc selftest
 Selftest: passed

This still sends the same command  4 (selftest) from netfn 6(application) to 
the target. However, to do so, the command is encapsulated (by the driver) and
sent using the command 0x34 (send message) from netfn 6(application) to KCS. 
Then KCS is polled by the driver until a message has been received, then the
driver uses command 0x33 (get message). The driver also tracks the message 
and makes sure the response matches the request. Then it decapsultates the
message and gives the response back to the application.

Dual Bridged Command
Things get a little more ugly when the application needs to reach a management
controller sitting on an interface (or channel) not directly connected to the 
BMC/IPMC. In the case the application must encapsulate its message itself and 
request the IPMC to deal with message tracking itself.

Its been working well with IPMITOOL on the LAN interface with:
 ipmitool -H <ip> -U <user> -P <password> -B 0 -T 0x8a  -m 0x20 -t 0x7a -b 7  
    mc selftest

However, trying to dual bridge commands locally with :
 ipmitool -B 0 -T 0x9a -m 0x94 -t 0x7a -b 7 mc selftest didn't work 
 (it returned the same data as  ipmitool -m 0x20 -t 0x7a -b 7 mc selftest )
The reason was that the "openipmi" interface pluging didn't 
encapsulate/decapsulate the message and didn't even detect the intent
to double bridge the request.

 ./src/ipmitool -B 0 -T 0x8a -m 0x94 -t 0x7a -b 7 mc selftest
-B    0  : transit channel for first bridge level (channel 0: IPMB-0) 
-T 0x8a  : transit destination address (remote IPMC address)
-m 0x94  : source address (local IPMC address on IPMB-0)
-t 0x7a  : remote target (AMC IPMB-L address)
-b    7  : remote channel (channel 7: IPMB-L)

The transit source address (remote IPMC address on remote channel) is 
automatically assigned by the remote IPMC.

Payload Size Limit
Because some commands return a lot of data (fru read/get sdr) and because 2 
levels of encapsulation are used, some command will fail.

For instance this works.

ipmitool -H <ip> -U <user> -P <password>  -B 0 -T 0x8a  -m 0x94 -t 0x7a -b 7 
    mc selftest

but this does not:
ipmitool -H <ip> -U <user> -P <password>  -B 0 -T 0x8a  -m 0x94 -t 0x7a -b 7 
    fru print.

All invocations of ipmitool require specifying an interface to use, unless
you want to use the default interface as set at compile time.  Each call
must also specify a command to run.  You can see the list of supported
interfaces and which is default as well as a list of top level commands in
the usage output available with the -h option:

usage: ipmitool [options...] <command>

   -h            This help
   -V            Show version information
   -v            Verbose (can use multiple times)
   -c            Display output in comma separated format
   -I intf       Interface to use
   -H hostname   Remote host name for LAN interface
   -p port       Remote RMCP port [default=623]
   -L level      Remote session privilege level [default=USER]
   -A authtype   Force use of authtype NONE, PASSWORD, MD2 or MD5
   -U username   Remote session username
   -P password   Remote session password
   -f file       Read remote session password from file
   -a            Prompt for remote password
   -E            Read password from IPMI_PASSWORD environment variable
   -m address    Set local IPMB address
   -t address    Bridge request to remote target address

    open         Linux OpenIPMI Interface [default]
    imb          Intel IMB Interface
    lan          IPMI v1.5 LAN Interface
    lanplus      IPMI v2.0 RMCP+ LAN Interface

    raw          Send a RAW IPMI request and print response
    lan          Configure LAN Channels
    chassis      Get chassis status and set power state
    event        Send pre-defined events to BMC
    bmc          Print BMC status and configure global enables
    sdr          Print Sensor Data Repository entries and readings
    sensor       Print detailed sensor information
    fru          Print built-in FRU and scan SDR for FRU locators
    sel          Print System Evelnt Log
    sol          Configure IPMIv2.0 Serial-over-LAN
    user         Configure BMC users
    channel      Configure BMC channels
    session      Print session information
    shell        Launch interactive IPMI shell
    exec         Run list of commands from file
    set          Set runtime variable for shell and exec

More help on the supported commands can be found by running them with the
help argument, for example "chassis help".  There are a few commands with
special meaning:

> shell:  This command will launch an shell interface to the ipmitool
  command set.  You can use this for interactively entering commands to
  monitor system status.  An example session:

# ipmitool -I open shell
ipmitool> chassis status
System Power         : off
Power Overload       : false
Power Interlock      : inactive
Main Power Fault     : false
Power Control Fault  : false
Power Restore Policy : always-off
Last Power Event     : command
Chassis Intrusion    : active
Front-Panel Lockout  : inactive
Drive Fault          : false
Cooling/Fan Fault    : false
ipmitool> user list 7
ID  Name             Callin  Link Auth  IPMI Msg   Channel Priv Limit
1                    true    false      true       ADMINISTRATOR
ipmitool> exit

> exec:  This command will read a text file and execute ipmitool commands
  in sequence.  It can be used for scriptable commands:

# cat lansetup.scr
lan set 7 ipsrc static
lan set 7 ipaddr
lan set 7 netmask
lan set 7 defgw ipaddr
# ipmitool -I open exec lansetup.scr
Setting LAN IP Address to
Setting Lan Subnet Mask to
Setting Lan Default Gateway IP to

> set:  This command can be used by the shell and exec modes to configure
  various session parameters:

  hostname <host>        Session hostname
  username <user>        Session username
  password <pass>        Session password
  privlvl <level>        Session privilege level force
  authtype <type>        Authentication type force
  localaddr <addr>       Local IPMB address
  targetaddr <addr>      Remote target IPMB address
  port <port>            Remote RMCP port
  csv [level]            enable output in comma separated format
  verbose [level]        Verbose level

# cat getstatus.scr
set hostname sf-v20z-1
set password admin
chassis status
# ipmitool -I lan exec getstatus.scr
Set session hostname to lx50
Set session password
System Power         : off
Power Overload       : false
Power Interlock      : inactive
Main Power Fault     : false
Power Control Fault  : false
Power Restore Policy : always-off
Last Power Event     : command
Chassis Intrusion    : active
Front-Panel Lockout  : inactive
Drive Fault          : false
Cooling/Fan Fault    : false

Included with ipmitool is another utility called ipmievd that is a daemon
which will listen for events from the BMC that are being sent to the SEL
and also log those messages to syslog.  By default when run (as root) with
no arguments it will daemonize and poll on the OpenIPMI device waiting for
an event notification.  Upon receipt of an event it will log it to syslog
with the LOG_LOCAL4 facility.  You can test ipmievd by sending test events
over the LAN interface with ipmitool:

remote# ipmievd

local$ ipmitool -I lan -H lx50 -P admin event help
usage: event <num>
   1 : Temperature - Upper Critical - Going High
   2 : Voltage Threshold - Lower Critical - Going Low
   3 : Memory - Correctable ECC
local$ ipmitool -I lan -H lx50 -P admin event 1
Sending Temperature - Upper Critical - Going High event to BMC
local$ ipmitool -I lan -H lx50 -P admin event 2
Sending Voltage Threshold - Lower Critical - Going Low event to BMC
local$ ipmitool -I lan -H lx50 -P admin event 3
Sending Memory - Correctable ECC event to BMC

remote# tail /var/log/messages   (timestamps removed)
ipmievd: Waiting for events...
ipmievd: Temperature Sensor 30 - Upper Critical - going high
ipmievd: Voltage Sensor 60 - Lower Critical - going low
ipmievd: Memory Sensor 01 - Correctable ECC

IPMItool homepage

IPMItool manpage

Intelligent Platform Management Interface specification

OpenIPMI project: Linux IPMI kernel driver and userland library

IPMItool commit archive