If i configure an IPMI interface in zabbix with correct login/priv-level, i get the following error in zabbix-frontend:
"cannot connect to IPMI host: [33554449] Unknown error 33554449"

in the console it works fine:
ipmitool -H 172.16.105.27 -U zabbix -P <PW> -L USER sdr
SEL | Not Readable | ns
Intrusion | 0x00 | ok
Fan1 RPM | 4440 RPM | ok
Fan2 RPM | 4560 RPM | ok
[...]

ipmitool -H 172.16.105.27 -U zabbix -P <PW> -L USER sensor
SEL | na | discrete | na | na | na | na | na | na | na
Intrusion | 0x0 | discrete | 0x0080| na | na | na | na | na | na
Fan1 RPM | 4440.000 | RPM | ok | na | 600.000 | 840.000 | na | na | na
Fan2 RPM | 4560.000 | RPM | ok | na | 600.000 | 840.000 | na | na | na
[...]

In attach the logfile and a tcpdump (open with wireshark)