AAAA type query invalidates A records in name server cache

[Chris Thompson]

On Jul 19 2011, mailsecurity wrote:

>All,
>
>anyone experiencing the same behavior?
>
>Seen on
>BIND 9.5.2-P2 and BIND 9.8.0-P4
>
> 
>
>ns11:~ # nslookup -querytype=A xserv.ins.dell.com.
>.....
>Non-authoritative answer:
>Name:   xserv.ins.dell.com
>Address: 143.166.148.118
>
>All ok.
>
>ns11:~ # nslookup -querytype=AAAA xserv.ins.dell.com.
>.....
>** server can't find xserv.ins.dell.com.: NXDOMAIN
>
>Now even the A queries fail.
>
>ns11:~ # nslookup -querytype=A xserv.ins.dell.com.
>.....
>** server can't find xserv.ins.dell.com.: NXDOMAIN
>
>Keeps failing until TTL timeout or rndc flushname xserv.ins.dell.com. 
>
>ns11:~ # nslookup -querytype=A xserv.ins.dell.com.
>.....
>Non-authoritative answer:
>Name:   xserv.ins.dell.com
>
>Address: 143.166.148.118

Yes, we had this reported last month (for premier.dell.co.uk which
CNAME chains to vandom.ins.dell.com, but the effect is exactly the same).

We reported it to dnsadmin at dell.com on 28 June. Deafening silence.

They should be returning "nodata" rather than NXDOMAIN for the AAAA
query, of course.

-- 
Chris Thompson
Email: cet1 at cam.ac.uk