DHCP lease names in DNS

Automatic lease DNS

Set registerDNS: true and use a dedicated domain such as lan.home.arpa. A bound lease named laptop answers at laptop.lan.home.arpa and has a PTR record. Reservation hostnames override client-supplied names. Offers, quarantined or expired addresses have no records. The earliest still-live bound claimant owns an unreserved name, across scopes sharing a domain. Later duplicates cannot suppress it; the earliest waiting claimant takes over when the owner ends. A reserved hostname is protected from claims by a different MAC, even when the reserved device is offline.

Claim order survives renewal and restart. Release, expiry, rename, DNS disable or domain reassignment ends the old claim. Public imports cannot take ownership from an existing live name. Conflicting configured reservation names suppress that name until corrected. DHCP names and MAC addresses are unauthenticated; clients can still claim unused names or impersonate a MAC. Use reservation hostnames for stable names, but MAC reservations do not prevent impersonation. Enforce required restrictions with IP/network policies and a restrictive default policy; hostname matching is advisory, and a missing match can select a fallback policy.

Option 12 hostnames have trailing NUL bytes stripped. Empty or unusable names are ignored, so an otherwise valid DHCP request can still obtain a lease. Malformed option framing and invalid configured reservation names are rejected.

Do not create a configured zone covering the DHCP domain. Specific primary or forward zones retain precedence, including their negative answers. A primary root also takes precedence. The default root forward zone is the exception: its catch-all route allows DHCP names to resolve locally. For example, a configured home.arpa zone hides DHCP names under lan.home.arpa; use a separate domain or reorganize the zones. Specific reverse zones likewise take precedence over generated PTRs.

The DHCP domain returns local negative answers for missing names, so dedicate it to leases. Unrelated DNS names continue through normal routing. Generated records do not appear in zone record editors, modify zone serials or export through zone transfers. TTL is the smaller of dnsTTL and remaining lease life. Server answers reflect committed changes immediately, while clients may retain an earlier answer until its TTL expires. Lease hostnames are also available to hostname/nameGlob client policy matching.