rndc and nsupdate failing to work for me

[John W. Blue]

Marc,

Regarding your rndc problem, I think you might be confusing rndc.

If rndc is invoked with no options, specifically “k”, then rndc assumes the key it needs is in the rndc.conf file.  If rndc.conf is not present, rndc will use the default rndc.key file.  That said, since rndc knows there is an /etc/rndc.key file but it choosing to use rndc.conf is the secret the same in both places?

As an option, instead of including /etc/rndc.key nothing prevents you from including rndc.conf.  That way you are consistent with your useage.

I personally do not use nsupdate, but I thought that key file had to be created by dnssec-keyen and if you opt to use “k” then the file suffix on the command line had to be “.private”.

Hope that helps and good hunting!

John

From: bind-users [mailto:bind-users-bounces at lists.isc.org] On Behalf Of Marc Chamberlin via bind-users
Sent: Wednesday, March 13, 2019 6:02 PM
To: bind-users at lists.isc.org
Subject: rndc and nsupdate failing to work for me


Hello Bind Users,

I have been working on upgrading my Bind 9.11.2 server (running on a Linux system, OpenSuSE Leap 15) so that I can accept DNS challenges/verification from/for LetsEncrypt certificates, and I am running into a wall trying to get nsupdate (and rndc which I wanted to use to test the server with) to work with the server. So I hope some kind guru here can lead me into the light cuz I am lost....

My configuration is really not all that complicated, I am running the server on a firewall computer that supports other services such as web and email services also. I have a SOHO internal network behind the firewall computer. I have configured the Bind (named) server with the 3 standard views - localhost.resolver, internal, and external. Since I support a number of virtual hosts and real hosts I have quit a few zones defined for each view. For regular queries and things like zone transfers the server is performing OK.

That said I will show what I think are the relevant definitions from my configuration files, with sensitive info redacted of course, and follow on with questions I have -

named.conf -

There is a bunch of stuff at the beginning of this file, but I think it is irrelevant to this issue. Correct me if I am wrong and I will be happy to post it...
include "/etc/rndc.key";
 controls {
       inet * port 953
               allow { any; } keys { "rndc-key"; };
 };
  view "localhost_resolver"
 {
        match-clients                 { localhost; };
        match-destinations      { localhost; };
... more stuff here but I don't think it is relevant

      include "/etc/named.d/local/local_zones.conf";
  }
view "internal" {
    match-clients      { 192.168.10.0/24; };
   match-destinations { 192.168.10.0/24; };
   recursion yes;
... more stuff here but I don't think it is relevant
include "/etc/named.d/internal/internal_zones.conf";
};
view "external" {
   match-clients      { any; };
   match-destinations { any; };
   recursion no;
... more stuff here but I don't think it is relevant
   include "/etc/named.d/external/external_zones.conf";
};

This seems pretty straightforward configuration in named.conf.  The configuration of a zone in the external view typically looks like this -

zone "mydomain.com" in {
    file "/etc/named.d/external/master/mydomain.com";
    type master;
    allow-transfer { "dnsmadeeasy1"; };
    also-notify { xx.xxx.xx.xxx; yyy.yyy.yy.yyy; zzz.zzz.zz.zz; };
        allow-query { any; };
        allow-update {
           key "letsencrypt";
        };
};

And this is what is in rndc.conf -
key "rndc-key" {
        algorithm hmac-md5;
        secret "secretkeycodehere";
 };
options {
        default-key "rndc-key";
        default-server localserver;
        default-port 953;
};
server localserver {
        addresses   { 127.0.0.1 port 953; };
        key "rndc-key";
};
server intserver {
        addresses   { 192.168.10.100 port 953; };
        key "rndc-key";
};
server extserver {
        addresses   { xxx.yyy.zzz.aaa port 953; };
        key "rndc-key";
};

Again, straightforward, and as I said normal queries do work....  However when I use rndc to poke at it, this is what happens -
# rndc showzone mydomain.com in external
WARNING: key file (/etc/rndc.key) exists, but using default configuration file (/etc/rndc.conf)
rndc: 'showzone' failed: failure

I don't understand why I am getting the warning, seems like a so what since the keys are identical in both locations. (I couldn't figure out if it is possible to use an include statement instead of the key definition in rndc.conf)  As for the failure when I asked it to do a showzone, I don't have a clue as to why this is failing. Log files are not helpful (and neither is this error message for that matter!)

I am also experiencing problems with nsupdate in that changes I make with it are not persistent across a restart of the named service. To demonstrate this I have a file called test.txt -

debug yes
zone mydomain.com.
update add test.mydomain.com. 86400 TXT "bar"
show
send

and if I use it as follows this is what I see -
# nsupdate -k /etc/letsencrypt/james/Kletsencrypt.+165+56715.key -v ./test.txt
I get lots of output and no indication of any problems. Using dig to see if the update indeed works -
 # dig +short -t txt test.mydomain.com "bar"
"bar"

it works, but if I restart the named service, no joy -

# systemctl restart named.service

# dig +short -t txt test.mydomain.com "bar"

#



the update is not persistent!  Any ideas?  Thanks in advance for helping me resolve these issues.    Marc...


--
Computers: the final frontier. These are the voyages of the user Marc.
His mission: to explore strange new hardware. To seek out new software and new applications.
To boldly go where no Marc has gone before!
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