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Asked: 2013-07-02 02:20:31 +0800 CST

Cannot make bind9 forward DNS query to subdomain unless recursive enabled

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I am trying to develop my own dynamic DNS. I'm running my own custom DNS for the subdomain on port 5353. ASCII diagram:

INET --->:53 Bind 9 --->:5353 node.js
               |
               V
           zone_files

I have example.com. The node.js DNS is for dyn.example.com.

In my /etc/bind/named.conf.local I have:

zone "example.com" {
    type master;
    file "/etc/bind/db.com.example";
    allow-transfer {
        zonetxfrsafe;
    };
};

zone "dyn.example.com" IN {
    # DYNAMIC
    type forward;
    forwarders { 127.0.0.1 port 5353; };
    forward only;
};

I've even gone so far as to add a NS in my example.com zone file:

$TTL    86400
@   IN  SOA ns.example.com. hostmaster.example.com. (
            2013070104  ; Serial
               7200     ; Refresh
               1200     ; Retry
            2419200     ; Expire
              86400 )   ; Negative Cache TTL
;
        NS  ns                    ; inet of our nameserver

ns      A   1.2.3.4

; NS record for subdomain
dyn     NS  ns

When I attempt to get a record from the subdomain server it doesn't get forwarded:

dig @127.0.0.1 test.dyn.example.com

However if I turn recursive on in /etc/bind/named.conf.options:

options {
  recursion yes;
}

.. then I CAN see the request going to the subdomain server.

But I don't want recursion yes; in my Bind configuration as it is poor security practice (and allows all-and-sundry requests that are not related to my managed zones).

How does one forward (proxy) zone queries for just one zone? Or do I give up on Bind altogether and find a DNS server that can actually forward specific queries?

bind

1 Answers

  1. This cannot be done. Query forwarding is a form of recursion, and this is behaving as expected.

    You must either set up your dynamic DNS as its own discrete nameserver, or perform zone transfers off of it.

    • 2