BIND 10 #504: CNAME Implementation

[BIND 10 Development]

#504: CNAME Implementation
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                 Reporter:  stephen  |                Owner:  jinmei
                     Type:           |               Status:  reviewing
  enhancement                        |            Milestone:  A-Team-
                 Priority:  major    |  Sprint-20110126
                Component:  data     |           Resolution:
  source                             |            Sensitive:  0
                 Keywords:           |  Add Hours to Ticket:  0
Estimated Number of Hours:  5.0      |          Total Hours:  0
                Billable?:  1        |
                Internal?:  0        |
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Comment (by each):

 About a month ago, there was a discussion on the ISC tech-staff mailing
 list about CNAME chaining behavior (ISC personnel can review it at
 https://wiki.isc.org/mhonarc/tech-staff/msg08812.html.)  We should have a
 discussion about this before going forward with CNAME handling in the
 authoritative server.

 Briefly: An authoritative server can believe itself to be authoritative
 for zones X and Y when actually it's only authoritative for X.  If we
 allow CNAME chains between two zones, we may be giving false information
 and claiming it's authoritative.  For example, a query for www.foo.com/A
 comes in could get back www.foo.com/CNAME and www.bar.com/A, which would
 be wrong if this server wasn't actually authoritative for bar.com.

 In my opinion we should not chain outside of a zone, including not below
 zone cuts.  In the linked discussion, Paul Vixie argued that we should not
 chain at all, even within the zone.

 Jinmei told me via jabber that the in-memory data source doesn't chase
 CNAME targets yet; in light of this I'd like to recommend that it not be
 taught to do so until we've had time to discuss the issue further.  (Note
 that the existing query logic for the SQL data source does return CNAME
 chains; this should probably be smartened up later.)

-- 
Ticket URL: <http://bind10.isc.org/ticket/504#comment:12>
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