Comment 3 for bug 1916860

We've seen something similar with drapion, a Lenovo x3650 M5, after upgrading from Ubuntu 18.04 and MAAS 2.6 to Ubuntu 20.04 and MAAS 2.9. As part of this upgrade, we ditched our old MAAS database and re-enlisted all the nodes. We are also unable to access the server's BMC using ipmitool:

$ ipmitool -I lanplus -H 10.245.129.49 -U username -P password chassis status
Error in open session response message : no matching cipher suite

The same ipmitool problem occurs when trying to access the BMC from another node deployed with Ubuntu 18.04 or even 16.04, which had led us to believe that the problem was a failure on the server (which had been fine prior to our MAAS upgrade); however, the same bug on another system after an upgrade to MAAS 2.9 brings that conclusion into doubt. Is it possible that MAAS enlisting the server is changing something in the BMC's configuration to create this problem?

Other things we've tried, without success, include:

* Rebooting the BMC
* Testing with every "Cipher Suite ID" option available in MAAS
* Upgrading the BMC's firmware to the latest version
* Upgrading the computer's main firmware to the latest version
* Enabling NIST SP 800-131A compliance mode in BMC (but this setting
  doesn't seem to have "taken")

The server's web UI remains accessible.

We're seeing the same problem on one other server, an IBM x3650 M2 (wildorange). This server is old enough that we weren't likely to keep it for long, but the newer M5 variant is still worth keeping.