Chuck Swiger cswiger at mac.com
Thu Nov 29 23:39:47 UTC 2012


On Nov 29, 2012, at 3:34 PM, Jose Manuel Delgado G. wrote:
> about the other question, as to reduce the response time of my server when the domain does not exist?

BIND implements negative caching of NXDOMAIN responses:

% dig www.does.not.exist. @localhost
[ ... ]
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 4942
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.does.not.exist.		IN	A

;; AUTHORITY SECTION:
.			10800	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2012112901 1800 900 604800 86400

;; Query time: 360 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Nov 29 18:35:52 2012
;; MSG SIZE  rcvd: 111

% dig www.does.not.exist. @localhost
[ ... ]
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 55697
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.does.not.exist.		IN	A

;; AUTHORITY SECTION:
.			10789	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2012112901 1800 900 604800 86400

;; Query time: 1 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Nov 29 18:36:03 2012
;; MSG SIZE  rcvd: 111

Regards,
-- 
-Chuck




More information about the bind-users mailing list