Problem: Baseboard management controller cannot get IP address?

I have a computer system whose motherboard has ASRock Rack baseboard management controller (BMC) that allows me to interact with the system via the Intelligent Platform Management Interface (PMI). One day, I noticed that the BMC ceases to have an IP address assigned. This is obviously a problem since the system does not have a monitor directly connect to it, and the management console was at the time the only means for me to administrate the system fully.

Neither of the following I attempted resolved the issue,

1. I unplug and re-plug the Ethernet cable to the Ethernet port of the BMC.
2. I reboot the network gateway that runs the DHCP server to allocate the IP address to it.
3. I shutdown the system, and reboot the system.  

Finally, I realized that the BMC is a little computer of its own, and I had never rebooted it at all despite the above attempts. With this in mind, I attempted the following solution and it worked!

• Unplug the power cable from the system and plug the power cable back to the system

This in retrospect is the means to reboot the BMC system. Having attempted this, I also wonder, what if I switch off the power switch of the power supply, would it also work? I guess it should be, it reboots the BMC system itself to cut off the power. So simple, after some frustration!

Clearing IPMI Log Entries

I saw this error message on my FreeNAS system,

IPMI SEL low space left: 0 bytes (100% used).

This can happen to any system. In my case, it is that motherboard battery somehow has low voltage and needs replacement. However, one issue is to clear the IPMI SEL log entries to make some space. The following command allows me to clear the log entries,

sudo ipmitool sel clear

Changing IPMI User Password

I was wondering how I would reset or change IPMI user password. The solution is actually simple, i.e., to use ipmitool.

Here is an example. I have a FreeNAS system running a server with a ASROCK Rack IPMI, and would do the following to change a IPMI user's password,

1. Query IPMI users ID
   

   
   sudo ipmitool  user list 1
   

   
   where "1" is the channel number. The outputs resembles the following,
   

   
   
   ID  Name             Callin  Link Auth  IPMI Msg   Channel Priv Limit
   1                    false   false      true       ADMINISTRATOR
   2   admin            false   false      true       ADMINISTRATOR
   3                    true    false      false      NO ACCESS
   4                    true    false      false      NO ACCESS
   5                    true    false      false      NO ACCESS
   6                    true    false      false      NO ACCESS
   7                    true    false      false      NO ACCESS
   8                    true    false      false      NO ACCESS
   9                    true    false      false      NO ACCESS
   10                   true    false      false      NO ACCESS
   

   
   where the admin user's ID is 2.
   
   
2. Change IPMI user password. The following is to change the "admin" user's password to admin123.
   

   
   sudo ipmitool  user set password 2 admin123
   

   
   where "2" is the ID of the admin user. 
   

We can also do the above on a Linux system. Note that these are for the host's IPMI.