[dns-operations] who cares about RA bit

[zhanglikun]

On Friday, June 17, 2011 7:41 AM, Mark wrote: 
> Stub resolvers expect recursive service.  Some answers get
> mis-interpretted if they don't get recursive service.  Some resolver
> libraries will skip servers that do not set RA in responses to
> queries with RD set.  If the caller of the library has requested
> recursive service then the library has to ensure that the answer
> returned is complete and the only way it can determine that is to
> look for RA.  If they don't see RA they move onto the next nameserver
> listed in resolv.conf or the equivalent.

A more specific question, should RA bit be set when the query is rejected by a pure resolver? (caused by ACL, or query is Update, XFR, etc. ), or if it is set, is there any bad point?


Thanks
Likun