David Howells wrote: Jim Rees <rees@xxxxxxxxx> wrote: > Define ENAMEUNKNOWN to indicate "Network name unknown". This can be used to > indicate, for example, that an attempt was made by dns_query() to make a query, > but the name server (e.g. a DNS server) replied indicating that it had no > matching records. > > Would this be the same as NXDOMAIN? That is, does it mean the name server > couldn't find a record, or does it mean that the record doesn't exist? Is there a way to tell the difference? Can you store a negative record in the DNS? Or is it that the DNS has records for the name, just not records of the type you're looking for (eg. NO_ADDRESS/NO_DATA from gethostbyname())? It's an important distinction to the resolver if you want to avoid dns hijacking. See rfc2308. There doesn't seem to be a way to tell the difference from the gethostbyname call, which was designed before this was a problem. The on-the-wire dns query protocol does make the distinction. I suspect kernel dns clients won't need to know the difference, but I think it's useful if we decide on and document the meaning of the error codes. Maybe the answer is that ENAMEUNKNOWN means the same as a HOST_NOT_FOUND from gethostbyname(). -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
