server: update comment
Because we have our own mux we can't depend on the dns.Mux to do the
Question section checking for us. Clarify this in the comment.
@@ -179,8 +179,8 @@ func (s *Server) Address() string { return s.Addr }
// defined in the request so that the correct zone
// (configuration and plugin stack) will handle the request.
func (s *Server) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
- // our dns library protects us against really invalid packets, we can still
- // get semi valid packets. Drop them here.
+ // The default dns.Mux checks the question section size, but we have our
+ // own mux here. Check if we have a question section. If not drop them here.
if r == nil || len(r.Question) == 0 {
DefaultErrorFunc(w, r, dns.RcodeServerFailure)
return
