Zone files where a label contains a literal . character (written as
\. in zone-file syntax) are currently rejected with:
a dot within a label is not currently supported
RFC 1035 permits this and both BIND and ldns accept such zones.
Adding support is not a small change. validns stores DNS names
internally as ASCII C strings using . as the label separator, so a
literal dot inside a label is indistinguishable from a label boundary.
Fixing this would require a different internal name representation
(e.g. wire format) along with corresponding changes to every RR type's
name handling, to NSEC / NSEC3 canonical ordering, to apex matching,
and to the zone-data store.
Split out from #34, which collects several smaller zone-parsing
issues; the remaining items there are being addressed separately.
This issue may end up closed as wontfix — literal dots in labels are
vanishingly rare in real zones and are widely discouraged. Filed so
the limitation is at least tracked explicitly.