dhcpd takes DHCP option 12 (hostname), lowercases it, strips a trailing dot, keeps only the first label, and drops characters that are not letter, digit, or hyphen. Max 63 characters.
That label is stored on the lease as hostname. If the subnet has DDNS and a forward zone, fqdn is hostname.zone.
Reservations can set a hostname on the form. Helpdesk search matches hostname.
DNS (/dns) shows lease-derived A/AAAA for leased FQDNs in the selected zone. Expire or release → NXDOMAIN after the outbox runs.
Do not put the token or client-id in a hostname. Do not expect option 12 with dots to become a multi-label FQDN — Lattice keeps one label on purpose.