Reported here: https://community.ipfire.org/t/not-all-local-hosts-resolve/5822/6 To the best of my knowledge, underscores are valid characters for FQDNs (unless they are terminal, I believe). Hence, we should process them when updating the Unbound dataset for a new DHCP client.
Underscores are valid for the Domain Name part of the FQDN but they are not valid for the hostname. See the subroutines validhostname, validdomainname and validfqdn in general-functions.pl
What is the issue being reported here? In what component?