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Disable named dns server from caching

Posted on 2005-05-09
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Last Modified: 2010-03-18
Is there any way to disable caching of hostname lookups when using a local named cache-only server. I know that sounds counterintuative, but I would like to have lookup requests hit the authoriative DNS servers and not use local cache. Is this possible?

If it isn't possible to configure the local nameserver to do this, is there a way to tell 'dig' or 'host' or 'nslookup' to not use the local cache, to basically ignore the TTL, and make the request directly to the authoritative nameservers?

Thanks in advance
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Question by:timdr
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4 Comments
 
LVL 18

Expert Comment

by:arantius
ID: 13964566
dig @nameserver host
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LVL 40

Expert Comment

by:jlevie
ID: 13965259
Or with host:

chaos> host -t ns redhat.com
redhat.com name server ns2.redhat.com.
redhat.com name server ns3.redhat.com.
redhat.com name server ns1.redhat.com.
chaos>
chaos> host www.redhat.com ns3.redhat.com
Using domain server:
Name: ns3.redhat.com
Address: 66.187.229.10#53
Aliases:
 
www.redhat.com has address 209.132.177.50
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Author Comment

by:timdr
ID: 13970011
Is there any way without specifiyinga nameserver to use? So that it finds this out on its own from the root servers?
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Accepted Solution

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arantius earned 2000 total points
ID: 13970353
$ chmod 750 authdig.sh
$ cat authdig.sh
#!/bin/sh
dig @`host -t ns $1|sed '1s/.*name server //;2,$d'` $1
$ ./authdig.sh redhat.com

; <<>> DiG 9.2.5 <<>> @ns1.redhat.com. redhat.com
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24655
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3

;; QUESTION SECTION:
;redhat.com.                    IN      A

;; ANSWER SECTION:
redhat.com.             60      IN      A       209.132.177.50

;; AUTHORITY SECTION:
redhat.com.             600     IN      NS      ns2.redhat.com.
redhat.com.             600     IN      NS      ns3.redhat.com.
redhat.com.             600     IN      NS      ns1.redhat.com.

;; ADDITIONAL SECTION:
ns1.redhat.com.         600     IN      A       66.187.233.210
ns2.redhat.com.         600     IN      A       66.187.224.210
ns3.redhat.com.         600     IN      A       66.187.229.10

;; Query time: 38 msec
;; SERVER: 66.187.233.210#53(66.187.233.210)
;; WHEN: Tue May 10 12:50:46 2005
;; MSG SIZE  rcvd: 146




(Yes the 3rd and 4th line above are the contents of the actual file, a small shell script)
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