check-mk and snmp

initializing my check-mk instance i ran into some problems, here are some tips for future reference.

Tip1: Sometimes the Full Scan does not provide any data. Here’s how to debug this on the command line (make sure to be the correct cmk user, root does not work!)

cmk --debug -vI HOST

…

ERROR: Cannot fetch system description OID .1.3.6.1.2.1.1.1.0. This might be OK for some bogus devices. In that case please configure the ruleset "Hosts without system description OID" to tell Check_MK not to fetch the system description and system object OIDs.

To make this work in “Access To Agents” you need to specify a rule for “Hosts without system description OID” edit the hostname and the snmp scan will work.