TL;DR
- ensure the IPMI network cable is connected before connecting the power cable
- ensure the IPMI LAN is using the dedicated interface
- ensure the IPMI LAN interface is connected to a “non green” port of your network switch
- ensure the DHCP server has been cold rebooted
- ensure the IPMI VLAN configuration matches your network
- ensure the IPMI firewall configuration matches the network you try to reach IPMI from
- ensure the motherboard does not have a short-circuit anywhere
Otherwise SuperMicro devices might not get a DHCP address on the IPMI (BMC) interface, despite the tooling like [WayBack] ipmicfg indicating getting DHCP was succesful.
This especially holds for X9 boards, likely for newer boards as well.
Personally I never had the 4. and up above, but I bumped into 1. and 2. with SuperMicro boards and 3. with other devices.