Most idmap backends don't need access to the domain controllers. And the related code is not needed for the backends. Commit 17c86a2c5a5a5e2b194362e5f36f0f99910222c5 changed the logic of set_domain_online_request() completely! Instead of triggering a dc probe in the background, it is now doing a blocking connection. And doing this in the idmap child is completely useless.
This bug was referenced in samba master: ad242a20643c930eb00a8b700f7bd9638f8821a8
Created attachment 17801 [details] git-am fix for 4.18.next, 4.17.next Cherry-picked from master.
Pushed to autobuild-v4-{18,17}-test.
This bug was referenced in samba v4-17-test: 148d5ad7698d154731dfa092b0c6314c71f38086
This bug was referenced in samba v4-18-test: 5c68985b2788330026df687d5439f4e86f90a77c
Closing out bug report. Thanks!
This bug was referenced in samba v4-18-stable (Release samba-4.18.2): 5c68985b2788330026df687d5439f4e86f90a77c
This bug was referenced in samba v4-17-stable (Release samba-4.17.8): 148d5ad7698d154731dfa092b0c6314c71f38086