Strange Log- Entries


I wonder how those log entries are created or better what may be the source of it?

I’m running an Active Directory Domain with name ourhome.local on a Synology NAS. I’ve configured IPFire’s DHCP as below and added some Domain name suffixes:

This configuration is running a long time and because of some troubles with my cable provider Vodafone, for about 10 days now, I see many of those Unbound records in log.

I think the source is IPFire or maybe the mandatory DNS server on the Synology NAS.

So any guess why some name resolution requests towards IPfire’s Unbound are postfixing my local domain name?

Any source I could additionally check?