DNSR-702 — Label contains incorrect character
According to RFC, label can contain only alphanumeric characters and hyphen ('-'). We allow also underscore ('_') and slash ('/') because they are commonly used. The printed label contains at printed (block) offset another character (printed). Only the first invalid character of name is logged.
In case of query, request is rejected with FormErr response code.
In case of reply, whole answer is ignored and next server is tried.