TitelHost with datasource program should not be force to have an IP address

You have a host that is monitored via a datasource program. This host has no DNS resolvable name, which is no problem sind Check_MK does not need to do a TCP connect. Nevertheless during the discovery Check_MK trries a DNS lookup and fails. But it should known that no IP adress is neccessary (since the datasource program command line does not contain <IP>. During the failed DNS lookup the datasource program is not being called. Better would be to use "" or as an IP address instead.