<div dir="auto">No idea if this is the best way. It is a way.</div><div dir="auto"><br></div><div dir="auto">Do you control any other zone? Let’s say you own “example.com.” You can tell ISC DHCP to build the reverse zone at an arbitrary base name instead of in-addr.arpa.</div><div dir="auto"><br></div><div dir="auto">Configure DHCP to put the reverse records at say, “rev.example.com.” So you’ll get records at,</div><div dir="auto"><br></div><div dir="auto"><a href="http://193.186.198.193.rev.example.com">193.186.198.193.rev.example.com</a></div><div dir="auto"><a href="http://194.186.198.193.rev.example.com">194.186.198.193.rev.example.com</a></div><div dir="auto">…</div><div dir="auto"><br></div><div dir="auto">And in your RFC 2317-style delegation, you then enumerate another CNAME layer,</div><div dir="auto"><br></div><div dir="auto">$ORIGIN 192-27.186.198.193.in-addr.arpa.</div><div dir="auto">193 IN CNAME <a href="http://193.186.198.193.rev.example.com">193.186.198.193.rev.example.com</a>.</div><div dir="auto">194 IN CNAME <a href="http://194.186.198.193.rev.example.com">194.186.198.193.rev.example.com</a>.</div><div dir="auto">…</div><div dir="auto"><br><div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Fri, Dec 10, 2021 at 2:51 PM Mirsad Goran Todorovac <<a href="mailto:mirsad.todorovac@alu.unizg.hr">mirsad.todorovac@alu.unizg.hr</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)">
<div>
<p><font face="monospace" style="font-family:monospace;color:rgb(0,0,0)">Hello,</font></p>
<p><font face="monospace" style="font-family:monospace;color:rgb(0,0,0)">I have a problem with DHCP DDNS update to
BIND 9 reverse PTR zone subnet that is owned by several
organizations, so I can't get a direct DHCP DDNS update access
with a key or with hostname.</font></p>
<p><font face="monospace" style="font-family:monospace;color:rgb(0,0,0)">I have been delegated domain name <code style="font-family:monospace">192-27.186.198.193.in-addr.arpa
from the upper level admins, and that appears to be immutable.</code></font></p>
<p><code style="font-family:monospace">However, my subnet is <a href="http://193.198.186.192/27" target="_blank" style="font-family:monospace">193.198.186.192/27</a>, and DHCP only
knows how to perform DDNS update to 186.198.193.in-addr.arpa.
(See here:
<a href="https://serverfault.com/questions/806875/how-to-tell-isc-dhcp-correct-zone-for-reverse-zone-ddns-update" target="_blank" style="font-family:monospace">https://serverfault.com/questions/806875/how-to-tell-isc-dhcp-correct-zone-for-reverse-zone-ddns-update</a>
and here: <a href="https://lists.isc.org/mailman/htdig/dhcp-users/2006-August/001422.html" target="_blank" style="font-family:monospace">https://lists.isc.org/mailman/htdig/dhcp-users/2006-August/001422.html</a>
).<br>
</code></p>
<p><code style="font-family:monospace">(This setup is because we have DHCP addresses that are not
over NAT, but /24 subnet is shared with other organizations,
even under another Minstry.)</code></p>
<p><code style="font-family:monospace">I want to have the effect of delegating the same database
to upper level under their zone name, while updating the same
database under my DHCP-understood zone name.</code></p>
<p><code style="font-family:monospace">I tried this /etc/bind/named.conf.local:</code></p>
<pre style="font-family:monospace"><code style="font-family:monospace">zone "192-27.186.198.193.in-addr.arpa" in {
type master;
file "/var/cache/bind/192-27.186.198.193.in-addr.arpa.db";
};
zone "186.198.193.in-addr.arpa" in {
type master;
file "/var/cache/bind/192-27.186.198.193.in-addr.arpa.db";
allow-update { key DDNS_UPDATE; };
};
</code></pre>
<font face="monospace" style="font-family:monospace;color:rgb(0,0,0)"> </font>
<p><font face="monospace" style="font-family:monospace;color:rgb(0,0,0)">(Two zones with the same file.)</font></p>
<font face="monospace" style="font-family:monospace;color:rgb(0,0,0)"> </font>
<p><font face="monospace" style="font-family:monospace;color:rgb(0,0,0)">What I got was:</font></p>
<font face="monospace" style="font-family:monospace;color:rgb(0,0,0)"> </font>
<pre style="font-family:monospace"><code style="font-family:monospace">root@domac:/etc/bind# named-checkconf
/etc/bind/named.conf.local:49: writeable file '/var/cache/bind/192-27.186.198.193.in-addr.arpa.db': already in use: /etc/bind/named.conf.local:44
root@domac:/etc/bind#
Can you please tell me is there a way to achieve the effect of the above (illegal) setup?
I can't change DHCP nor I know an option to tell it to accept update to </code><code style="font-family:monospace"><code style="font-family:monospace">192-27.186.198.193.in-addr.arpa</code>
(it is a syntax error).
The DHCP dhcpd.conf subnet configuration is:
</code><code style="font-family:monospace"><code style="font-family:monospace">subnet 193.198.186.192 netmask 255.255.255.224 {
range 193.198.186.200 193.198.186.222; # MT 20211210
option subnet-mask 255.255.255.224;
option domain-name-servers 161.53.235.3, 161.53.2.70;
option domain-name "<a href="http://slava.alu.hr" target="_blank" style="font-family:monospace">slava.alu.hr</a>";
ddns-domainname "<a href="http://slava.alu.hr" target="_blank" style="font-family:monospace">slava.alu.hr</a>";
zone <a href="http://slava.alu.hr" target="_blank" style="font-family:monospace">slava.alu.hr</a>. {
primary 127.0.0.1;
key DDNS_UPDATE;
}
zone 186.198.193.in-addr.arpa. {
primary 127.0.0.1;
key DDNS_UPDATE;
}
option broadcast-address 193.198.186.223;
option routers 193.198.186.193;
default-lease-time 43200;
max-lease-time 86400;
}
</code>
Thank you very much for your time reading this mail and help.
Kind regards,
--
Mirsad Goran Todorovac
Academy of Fine Arts | Faculty of Graphic Arts
University of Zagreb
</code></pre>
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