[Samba] Configure DHCP to update DNS records with BIND9
Christian Naumer
cn at brain-biotech.de
Fri Jul 14 12:43:30 UTC 2017
Hallo all,
I configured DHCPD on two of my DCs to update the DNS records according to the wiki (https://w
iki.samba.org/index.php/Configure_DHCP_to_update_DNS_records_with_BIND9).
This works fine except when a lease expires the records are not deleted.
In the log I see this with an added record:
Jul 7 07:46:12 dc1 dhcpd: execute_statement argv[0] = /etc/dhcp/bin/dhcp-dyndns.sh
Jul 7 07:46:12 dc1 dhcpd: execute_statement argv[1] = add
Jul 7 07:46:12 dc1 dhcpd: execute_statement argv[2] = 192.168.X.X
Jul 7 07:46:12 dc1 dhcpd: execute_statement argv[3] = 1:0:00:00:00:00:00
Jul 7 07:46:12 dc1 dhcpd: execute_statement argv[4] = NAME
When a lease expires I see this:
Jul 7 07:46:09 dc1 dhcpd: execute_statement argv[0] = /etc/dhcp/bin/dhcp-dyndns.sh
Jul 7 07:46:09 dc1 dhcpd: execute_statement argv[1] = delete
Jul 7 07:46:09 dc1 dhcpd: execute_statement argv[2] = 192.168.X.X
Jul 7 07:46:09 dc1 dhcpd: execute_statement argv[3] =
Jul 7 07:46:09 dc1 dhcpd: execute_statement argv[4] = 0
Jul 7 07:46:09 dc1 dhcpd: USAGE:
Jul 7 07:46:09 dc1 dhcpd: dhcp-dyndns.sh add ip-address dhcid|mac-address hostname
Jul 7 07:46:09 dc1 dhcpd: dhcp-dyndns.sh delete ip-address dhcid|mac-address
Jul 7 07:46:09 dc1 dhcpd: execute: /etc/dhcp/bin/dhcp-dyndns.sh exit status 256
I the wiki the lines for adding a record in "/etc/dhcp/dhcpd.conf" are
execute("/etc/dhcp/bin/dhcp-dyndns.sh", "add", ClientIP, ClientDHCID, ClientName);
for deletion
execute("/etc/dhcp/bin/dhcp-dyndns.sh", "delete", ClientIP, "", "0");
as you can see the Name should be argv[4] the MAC should be argv[3]. For deletion this isn't
the case and the script checks for MAC (# Exit if no ip address or mac-address) and exits with
usage.
I checked this running this by hand:
runuser -l dhcpd -c "/etc/dhcp/bin/dhcp-dyndns.sh delete 192.168.6.1 0"
works
runuser -l dhcpd -c "/etc/dhcp/bin/dhcp-dyndns.sh delete 192.168.6.1 '' 0"
does not.
As it works for the author I think this might be distribution specific (I am on Centos 7)
thing of interpreting ""?
I have changed my dhcp.conf to include this when a lease expires:
execute("/etc/dhcp/bin/dhcp-dyndns.sh", "delete", ClientIP,"0");
This works for us. Should this be added to the WIKI?
hope this helps somebody.
Regards
Christian
--
Dr. Christian Naumer
Research Scientist
Plattform-Koordinator Bioprozesstechnik
B.R.A.I.N Aktiengesellschaft
Darmstaedter Str. 34-36, D-64673 Zwingenberg
e-mail cn at brain-biotech.de, homepage www.brain-biotech.de
fon +49-6251-9331-30 / fax +49-6251-9331-11
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Registergericht AG Darmstadt, HRB 24758
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Aufsichtsratsvorsitzender: Dr. Ludger Mueller
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