Currently Zabbix has issues with BMCs supporting only RMCP+ but a limited list of RMCP+ authentication/integrity/confidentiality schemes not matching OpenIPMI defaults. It manifests as 'Invalid argument (22)' error with RMCP+, error 16777441 when not using RMCP+, and so on.

A good example is Dell iDRAC 6 module. It cannot be queried by Zabbix IPMI checks because of that.

I am attaching a patch that enforces all RMCP+ channel authentication/integrity/confidentiality parameters to BMC specified.

This patch is better extended by Zabbix team to add real options for RMCP+ authentication/integrity/confidentiality modes to the web interface. This is just 'proof of concept' patch making BMC rule the communication options that indeed works when using RMCP+ at least on iDRAC 6.