Yahoo DNS broken?

Michael Sinatra michael at rancid.berkeley.edu
Wed Dec 3 14:46:20 CST 2008


On 12/03/08 12:36, Larry Daberko wrote:
> I am unable to resolve www.yahoo.com.  Tracing DNS back from the root
> servers shows that www.yahoo.com is a CNAME to www.wa1.b.yahoo.com and
> there are no A records for that hostname.
> 
> Anyone have more details or a Yahoo contact?  I'm unable to get to their
> webpage as it is :-)
> 
> -Larry Daberko
> iServe Technologies
> 
> 
> 
>  
> $ dig @ns1.yahoo.com www.yahoo.com
>  
> ; <<>> DiG 9.4.2 <<>> @ns1.yahoo.com www.yahoo.com
> ; (1 server found)
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56431
> ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
> ;; WARNING: recursion requested but not available
>  
> ;; QUESTION SECTION:
> ;www.yahoo.com.                 IN      A
>  
> ;; ANSWER SECTION:
> www.yahoo.com.          300     IN      CNAME   www.wa1.b.yahoo.com.
>  
> ;; AUTHORITY SECTION:
> wa1.b.yahoo.com.        300     IN      NS      yf1.yahoo.com.
> wa1.b.yahoo.com.        300     IN      NS      yf2.yahoo.com.
>  
> ;; ADDITIONAL SECTION:
> yf1.yahoo.com.          1800    IN      A       68.142.254.15
> yf2.yahoo.com.          1800    IN      A       68.180.130.15
>  
> ;; Query time: 15 msec
> ;; SERVER: 68.180.131.16#53(68.180.131.16)
> ;; WHEN: Wed Dec  3 15:34:09 2008
> ;; MSG SIZE  rcvd: 123
> 
>  
> but looking up the host itself gives no answer
>  
>  
> $ dig @ns1.yahoo.com www.wa1.b.yahoo.com
>  
> ; <<>> DiG 9.4.2 <<>> @ns1.yahoo.com www.wa1.b.yahoo.com
> ; (1 server found)
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34875
> ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
> ;; WARNING: recursion requested but not available
>  
> ;; QUESTION SECTION:
> ;www.wa1.b.yahoo.com.           IN      A
>  
> ;; AUTHORITY SECTION:
> wa1.b.yahoo.com.        300     IN      NS      yf1.yahoo.com.
> wa1.b.yahoo.com.        300     IN      NS      yf2.yahoo.com.
>  
> ;; ADDITIONAL SECTION:
> yf1.yahoo.com.          1800    IN      A       68.142.254.15
> yf2.yahoo.com.          1800    IN      A       68.180.130.15

Well, since ns1.yahoo.com isn't authoritative for wa1.b.yahoo.com, then 
I wouldn't expect it to have the answer.  Trying yf1.yahoo.com:

 > dig www.wa1.b.yahoo.com. @yf1.yahoo.com

; <<>> DiG 9.4.2-P1 <<>> www.wa1.b.yahoo.com. @yf1.yahoo.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31055
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;www.wa1.b.yahoo.com.           IN      A

;; ANSWER SECTION:
www.wa1.b.yahoo.com.    60      IN      CNAME   www-real.wa1.b.yahoo.com.
www-real.wa1.b.yahoo.com. 60    IN      A       209.131.36.158

;; Query time: 3 msec
;; SERVER: 68.142.254.15#53(68.142.254.15)
;; WHEN: Wed Dec  3 12:55:24 2008
;; MSG SIZE  rcvd: 76

It's a chain of CNAME records, which isn't very nice, but isn't 
technically illegal.  In most cases, it's resolvable.  Not what I would 
do for a globally-reachable revenue-generating service, but I am sure 
they have their reasons.

michael




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