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I've bind 9.3.6.

How can I disable hostname disclosure ?

Issue link


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The document you link to says There is no remedy as of December 18, 2010 – Iain Dec 23 '10 at 16:51
@Iain even though that message was updated 2 days ago, and remains unchanged, it is still incorrect. – NOTjust -- user4304 Dec 3 '13 at 18:20
up vote 2 down vote accepted

You can hide hostname and version this way:

# /etc/named.conf
options {
    // hide bind info
    hostname "unknown";
    version "unknown";

Hostname querying example:

[vitalie@silver ~]$ dig hostname.bind chaos txt

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> hostname.bind chaos txt
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46430
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0

;hostname.bind.                 CH      TXT

hostname.bind.          0       CH      TXT     ""

hostname.bind.          0       CH      NS      hostname.bind.

;; Query time: 6 msec
;; WHEN: Wed Jan  5 15:08:14 2011
;; MSG SIZE  rcvd: 72
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version "unknown" will return the string "unknown". version "none" will actually disable the feature. – TomOnTime Aug 20 '13 at 14:49

"There is no remedy as of December 18, 2010." Wrong, so very wrong. There has been a fix since February 2006 (at least). Put this in your BIND config (it probably is there already):

options {
  version "none";

Let me "craft" this "special" query (don't attempt this at home):

$ nslookup -q=txt -class=CHAOS authors.bind. localhost
Server:         localhost

*** Can't find authors.bind.: No answer

For more info on securing BIND have a look at

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To be clear... the string "none" is special in that it disables the feature. This does not happen if you set it to "unknown" or anything else. – TomOnTime Aug 20 '13 at 14:51
Is there a way to disable hostname.bind query as well? – RustyX Aug 27 '14 at 20:07

You can disable hostname.bind by putting this in named.conf (valid in BIND 9.9 that I use):

options {  
  hostname none;  
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