DNS named.conf

Posted on 2013-06-20
Last Modified: 2013-06-22

I am a bit on a dead end and think I need to have a second set of eyes look at this since I seem to not be able to hide my dns version with the suggested

version "unknown";
version unknown;

bot do not work.
I set it and restart but I do a DIG and it still shows the version.

Now while i show part of my conf file if you see any other issue please let me know.

option.  here is my named.conf and I wonder if you see something that would prevent it from hiding the version.

options {
      allow-query {
      allow-recursion { trusted; };
           allow-query-cache { trusted; };
      listen-on port 53 { trusted; };
      listen-on-v6 port 53 { ::1; };
      directory       "/var/named/";
      dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
      recursion yes;
      empty-zones-enable no;
      dnssec-enable yes;
      dnssec-validation yes;

      /* Path to ISC DLV key */
      bindkeys-file "/etc/named.iscdlv.key";
      managed-keys-directory "/var/named/dynamic";
          version "unknown";

any idea of there is something in options what could prevent the version unknown; from hiding my DNS version?

Thank you for the help.

Best wishes,
Question by:Thomanji
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LVL 68

Expert Comment

ID: 39262281
I think it's your client's local nscd showing you old version info from its cache.

Author Comment

ID: 39262302
Interesting, would make sense but it seems it is not installed. Just searched for it but only have some.


> nscd -i
> -bash: nscd: command not found

I think I might just need to wait for it to resolve but this was not mentioned on any of my google results. Well lets see, maybe time resolves it.

Do you see any other issue or security hole in my options block?

Best wishes,
LVL 68

Expert Comment

ID: 39262322
Your config looks good so far.

I guess you know it already, but let me point you to the "BIND 9 Security Vulnerability Matrix" nonetheless. Maybe it has something useful for you.
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LVL 28

Accepted Solution

Jan Springer earned 500 total points
ID: 39262418
Are you querying the server directly?

dig @A.B.C.D chaos txt version.bind

where A.B.C.D is the IP address of the DNS server.

Author Comment

ID: 39267514

I just did dig one of the domains from another server.


; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.4 <<>>
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1116
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2

;                   IN      A

;; ANSWER SECTION:            3600    IN      A

;; AUTHORITY SECTION:            3600    IN      NS            3600    IN      NS

;; ADDITIONAL SECTION:           38400   IN      A           38400   IN      A

;; Query time: 0 msec
;; WHEN: Fri Jun 21 23:41:50 2013
;; MSG SIZE  rcvd: 121

actually it times out if I use the version dig

dig @ chaos txt version.bind

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.4 <<>> @ chaos txt version.bind
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

I think I need to speak to the data centre and see if there is something in between.
It is complexly strange to me that it does not hide the version, however I am now suspecting that it might hit the data center because the 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.4 does not seem to be my server since I am running CentOS. Then again I do not understand why it would do this.

I will contact them and then update here too.

Best wishes,
LVL 28

Expert Comment

by:Jan Springer
ID: 39267992
I see your changes:

; (1 server found)                                                                          
;; global options: +cmd                                                                    
;; Got answer:                                                                              
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48504                                  
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;version.bind.                  CH      TXT

version.bind.           0       CH      TXT     "unknown"

version.bind.           0       CH      NS      version.bind.

;; Query time: 83 msec
;; WHEN: Sat Jun 22 08:05:29 2013
;; MSG SIZE  rcvd: 64

Author Closing Comment

ID: 39268052
Yes, I did it wrong. From the outside its working now.
Thank to point me to realize.

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