Werk #20037: No superfluous DNS lookups for hosts without an IP address

Component	Core & setup
Title	No superfluous DNS lookups for hosts without an IP address
Date	Jul 13, 2026
Level	Trivial Change
Class	Bug Fix
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	3.0.0b1 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT 2.5.0p9 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

Hosts configured with the IP address family No IP (for example piggyback hosts) have no IP address that could be monitored. Nevertheless, Checkmk still performed a DNS lookup for the management board of every such host, because the management board lookup was carried out unconditionally and fell back to resolving the host name.

In setups with many hosts without an IP address this caused a large number of pointless DNS queries during data fetching, automations, command-line calls and configuration generation. Depending on the DNS setup this could slow these operations down considerably or lead to further problematic symptoms.

Checkmk now skips the DNS lookup for the management board of a host that has no IP address family. An explicitly configured management address (IP address or host name) is still resolved as before.

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