TTL Caching

[Tim Maestas]

> 
> Does their server actually *answer* with both of those A records, having
> identical RDATA values and different TTLs?
> 
> That would violate RFC 2181 in a big way; section 5 (suppression of duplicate
> records) *and* section 5.2 (minimization of TTLs within an RRset) .
> 

	No, these are all queries against a BIND server.  This
	is how things are appearing on the Win2k client resolver
	cache.  If the BIND server has the following records:
	
	tim	50	IN	A	192.168.1.1
	cname	30	IN	CNAME	tim

	a query for tim will result in a cache of

	tim    50 192.168.1.1
	cname  30 tim
	tim    30 192.168.1.1

	along with additional and authority records being cached
	at 30 seconds regardless of what they really are.

	If you *reverse* the ttls, ie:
	tim 30 IN A 192.168.1.1
	cname 50 IN CNAME tim

	a query for tim will result in a cache of:
	tim 30 192.168.1.1
    	cname 30 IN CNAME tim

	Which MS claims is legal according to rfc2181.

-Tim