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Mark Petersen

2020-May-19 21:29 UTC

[Samba] DHCP Updates to DNS - Multiple Entries with Same IP

Thank you to Rowland, L.P.H. van Belle, the entire samba team, and others that
help. I've been running samba in our fire department for over a year.

I'm running a self compiled samba version 4.11.9, bind version 9.11.3,
BIND9_DLZ, isc-dhcp-server version 4.3.5 with fail over (between the 2 DC's)
on Ubuntu 18.04 on Odroid N2 aarch64. I have 2 identical DC's on the network
FDDC10 (172.20.10.70)& FDDC11 (172.20.10.71)

I'm having difficulties with dhcpd updating DNS entries.

In the journal I see this:

root at fddc11:~# journalctl --since 11:00
May 19 11:00:00 fddc11 sh[5403]: Record deleted successfully
May 19 11:00:01 fddc11 sh[5403]: Record added successfully
May 19 11:00:01 fddc11 dhcpd[1961]: DHCP-DNS Update failed: 0:255:0:0
May 19 11:00:01 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 256
May 19 11:00:01 fddc11 dhcpd[5403]: reuse_lease: lease age 66 (secs) under 25%
threshold, reply
with unaltered, existing lease for 172.20.10.152
May 19 11:00:01 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.152 from
78:3a:84:bc:2c:db
(Aarons-iPad) via eth0
May 19 11:00:01 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.152 to
78:3a:84:bc:2c:db (Aarons-iPad) via
eth0
May 19 11:00:01 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.152 DHCID:
78:3a:84:bc:2c:db Name:
Aarons-iPad
May 19 11:00:01 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:00:01 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:00:01 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.152
May 19 11:00:01 fddc11 dhcpd[5403]: execute_statement argv[3] =
78:3a:84:bc:2c:db
May 19 11:00:01 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPad
May 19 11:00:01 fddc11 sh[5403]: Record deleted successfully
May 19 11:00:02 fddc11 sh[5403]: Record added successfully
May 19 11:00:03 fddc11 sh[5403]: 172.20.10
May 19 11:00:03 fddc11 sh[5403]: 172.20.10
May 19 11:00:03 fddc11 sh[5403]: 152
May 19 11:00:03 fddc11 sh[5403]: ERROR(runtime): uncaught exception - (9701,
'WERR_DNS_ERROR_RECORD_DOES_NOT_EXIST')
May 19 11:00:03 fddc11 sh[5403]: File
"/usr/local/samba/lib/python3.6/site-packages/samba/netcmd/__init__.py",
line 186, in _run
May 19 11:00:03 fddc11 sh[5403]: return self.run(*args, **kwargs)
May 19 11:00:03 fddc11 sh[5403]: File
"/usr/local/samba/lib/python3.6/site-packages/samba/netcmd/dns.py",
line 1071, in run
May 19 11:00:03 fddc11 sh[5403]: raise e
May 19 11:00:03 fddc11 sh[5403]: File
"/usr/local/samba/lib/python3.6/site-packages/samba/netcmd/dns.py",
line 1067, in run
May 19 11:00:03 fddc11 sh[5403]: del_rec_buf)
May 19 11:00:04 fddc11 sh[5403]: Record added successfully
May 19 11:00:04 fddc11 dhcpd[2027]: DHCP-DNS Update failed: 0:0:255:0
May 19 11:00:04 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 256
May 19 11:00:04 fddc11 dhcpd[5403]: reuse_lease: lease age 70 (secs) under 25%
threshold, reply
with unaltered, existing lease for 172.20.10.152
May 19 11:00:04 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.152 from
78:3a:84:bc:2c:db
(Aarons-iPad) via eth0
May 19 11:00:04 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.152 to
78:3a:84:bc:2c:db (Aarons-iPad) via
eth0
May 19 11:00:59 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.226 DHCID:
40:88:05:41:19:85 Name:
android-68ef5da7aac0cd5e
May 19 11:00:59 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:00:59 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:00:59 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.226
May 19 11:00:59 fddc11 dhcpd[5403]: execute_statement argv[3] =
40:88:05:41:19:85
May 19 11:00:59 fddc11 dhcpd[5403]: execute_statement argv[4] =
android-68ef5da7aac0cd5e
May 19 11:01:00 fddc11 sh[5403]: Record deleted successfully
May 19 11:01:01 fddc11 sh[5403]: Record added successfully
May 19 11:01:01 fddc11 sh[5403]: 172.20.10
May 19 11:01:01 fddc11 sh[5403]: 226
May 19 11:01:02 fddc11 sh[5403]: Record deleted successfully
May 19 11:01:03 fddc11 sh[5403]: Record added successfully
May 19 11:01:03 fddc11 dhcpd[2092]: DHCP-DNS Update succeeded
May 19 11:01:04 fddc11 dhcpd[2103]: Computer 'android-68ef5da7aac0cd5e'
not found. Exiting.
May 19 11:01:04 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:01:04 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.226 from
40:88:05:41:19:85
(android-68ef5da7aac0cd5e) via eth0
May 19 11:01:04 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.226 to
40:88:05:41:19:85
(android-68ef5da7aac0cd5e) via eth0
May 19 11:05:53 fddc11 dhcpd[5403]: Expired: IP: 172.20.10.172
May 19 11:05:53 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:05:53 fddc11 dhcpd[5403]: execute_statement argv[1] = delete
May 19 11:05:53 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.172
May 19 11:05:53 fddc11 dhcpd[5403]: execute_statement argv[3] May 19 11:05:53
fddc11 dhcpd[5403]: execute_statement argv[4] = 0
May 19 11:05:54 fddc11 sh[5403]: USAGE:
May 19 11:05:54 fddc11 sh[5403]: dhcp-dyndns.sh add ip-address dhcid|mac-address
hostname
May 19 11:05:54 fddc11 sh[5403]: dhcp-dyndns.sh delete ip-address
dhcid|mac-address
May 19 11:05:54 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 256
May 19 11:06:04 fddc11 dhcpd[5403]: DHCPDISCOVER from 54:2b:8d:8a:54:79 via
eth0: load balance to
peer dhcp-failover
May 19 11:07:52 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.161 DHCID:
18:e8:29:96:6e:d4 Name:
Hallway
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.161
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[3] =
18:e8:29:96:6e:d4
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[4] = Hallway
May 19 11:07:53 fddc11 sh[5403]: Record deleted successfully
May 19 11:07:54 fddc11 sh[5403]: Record added successfully
May 19 11:07:55 fddc11 sh[5403]: 172.20.10
May 19 11:07:55 fddc11 sh[5403]: 172.20.10
May 19 11:07:55 fddc11 sh[5403]: 161
May 19 11:07:55 fddc11 sh[5403]: Record deleted successfully
May 19 11:07:56 fddc11 sh[5403]: Record added successfully
May 19 11:07:56 fddc11 dhcpd[2195]: DHCP-DNS Update succeeded
May 19 11:07:56 fddc11 dhcpd[2207]: Computer 'Hallway' not found.
Exiting.
May 19 11:07:56 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:07:56 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.161 from
18:e8:29:96:6e:d4 (Hallway)
via eth0
May 19 11:07:56 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.161 to
18:e8:29:96:6e:d4 (Hallway) via
eth0
May 19 11:12:49 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.164 DHCID:
c0:ee:fb:20:96:46 Name:
dhcp-172-20-10-164
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.164
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[3] =
c0:ee:fb:20:96:46
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[4] =
dhcp-172-20-10-164
May 19 11:12:49 fddc11 dhcpd[2229]: not updating DNS record in AD, invalid name
May 19 11:12:49 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.164 from
c0:ee:fb:20:96:46 via eth0
May 19 11:12:49 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.164 to
c0:ee:fb:20:96:46 via eth0
lines 63-91
May 19 11:05:54 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 256
May 19 11:06:04 fddc11 dhcpd[5403]: DHCPDISCOVER from 54:2b:8d:8a:54:79 via
eth0: load balance to
peer dhcp-failover
May 19 11:07:52 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.161 DHCID:
18:e8:29:96:6e:d4 Name:
Hallway
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.161
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[3] =
18:e8:29:96:6e:d4
May 19 11:07:52 fddc11 dhcpd[5403]: execute_statement argv[4] = Hallway
May 19 11:07:53 fddc11 sh[5403]: Record deleted successfully
May 19 11:07:54 fddc11 sh[5403]: Record added successfully
May 19 11:07:55 fddc11 sh[5403]: 172.20.10
May 19 11:07:55 fddc11 sh[5403]: 172.20.10
May 19 11:07:55 fddc11 sh[5403]: 161
May 19 11:07:55 fddc11 sh[5403]: Record deleted successfully
May 19 11:07:56 fddc11 sh[5403]: Record added successfully
May 19 11:07:56 fddc11 dhcpd[2195]: DHCP-DNS Update succeeded
May 19 11:07:56 fddc11 dhcpd[2207]: Computer 'Hallway' not found.
Exiting.
May 19 11:07:56 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:07:56 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.161 from
18:e8:29:96:6e:d4 (Hallway)
via eth0
May 19 11:07:56 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.161 to
18:e8:29:96:6e:d4 (Hallway) via
eth0
May 19 11:12:49 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.164 DHCID:
c0:ee:fb:20:96:46 Name:
dhcp-172-20-10-164
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.164
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[3] =
c0:ee:fb:20:96:46
May 19 11:12:49 fddc11 dhcpd[5403]: execute_statement argv[4] =
dhcp-172-20-10-164
May 19 11:12:49 fddc11 dhcpd[2229]: not updating DNS record in AD, invalid name
May 19 11:12:49 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.164 from
c0:ee:fb:20:96:46 via eth0
May 19 11:12:49 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.164 to
c0:ee:fb:20:96:46 via eth0
May 19 11:13:32 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.188 DHCID:
ec:ce:d7:5e:92:a6 Name:
Aarons-iPhone
May 19 11:13:32 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:13:32 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:13:32 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.188
May 19 11:13:32 fddc11 dhcpd[5403]: execute_statement argv[3] =
ec:ce:d7:5e:92:a6
May 19 11:13:32 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPhone
May 19 11:13:33 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:33 fddc11 sh[5403]: Record added successfully
May 19 11:13:34 fddc11 sh[5403]: 172.20.10
May 19 11:13:34 fddc11 sh[5403]: 172.20.10
May 19 11:13:34 fddc11 sh[5403]: 188
May 19 11:13:35 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:35 fddc11 sh[5403]: Record added successfully
May 19 11:13:35 fddc11 dhcpd[2286]: DHCP-DNS Update succeeded
May 19 11:13:36 fddc11 dhcpd[2297]: Computer 'Aarons-iPhone' not found.
Exiting.
May 19 11:13:36 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:13:36 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.188 from
ec:ce:d7:5e:92:a6
(Aarons-iPhone) via eth0
May 19 11:13:36 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.188 to
ec:ce:d7:5e:92:a6 (Aarons-iPhone)
via eth0
May 19 11:13:36 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.188 DHCID:
ec:ce:d7:5e:92:a6 Name:
Aarons-iPhone
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.188
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[3] =
ec:ce:d7:5e:92:a6
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPhone
May 19 11:13:37 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:37 fddc11 sh[5403]: Record added successfully
May 19 11:13:38 fddc11 sh[5403]: 172.20.10
May 19 11:13:38 fddc11 sh[5403]: 188
May 19 11:13:35 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:35 fddc11 sh[5403]: Record added successfully
May 19 11:13:35 fddc11 dhcpd[2286]: DHCP-DNS Update succeeded
May 19 11:13:36 fddc11 dhcpd[2297]: Computer 'Aarons-iPhone' not found.
Exiting.
May 19 11:13:36 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:13:36 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.188 from
ec:ce:d7:5e:92:a6
(Aarons-iPhone) via eth0
May 19 11:13:36 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.188 to
ec:ce:d7:5e:92:a6 (Aarons-iPhone)
via eth0
May 19 11:13:36 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.188 DHCID:
ec:ce:d7:5e:92:a6 Name:
Aarons-iPhone
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.188
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[3] =
ec:ce:d7:5e:92:a6
May 19 11:13:36 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPhone
May 19 11:13:37 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:37 fddc11 sh[5403]: Record added successfully
May 19 11:13:38 fddc11 sh[5403]: 172.20.10
May 19 11:13:38 fddc11 sh[5403]: 188
May 19 11:13:39 fddc11 sh[5403]: Record deleted successfully
May 19 11:13:39 fddc11 sh[5403]: Record added successfully
May 19 11:13:40 fddc11 dhcpd[2360]: DHCP-DNS Update succeeded
May 19 11:13:40 fddc11 dhcpd[2371]: Computer 'Aarons-iPhone' not found.
Exiting.
May 19 11:13:40 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:13:40 fddc11 dhcpd[5403]: reuse_lease: lease age 4 (secs) under 25%
threshold, reply with
unaltered, existing lease for 172.20.10.188
May 19 11:13:40 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.188 from
ec:ce:d7:5e:92:a6
(Aarons-iPhone) via eth0
May 19 11:13:40 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.188 to
ec:ce:d7:5e:92:a6 (Aarons-iPhone)
via eth0
May 19 11:13:40 fddc11 dhcpd[5403]: bind update on 172.20.10.188 from
dhcp-failover rejected:
incoming update is less critical than outgoing update
May 19 11:14:52 fddc11 dhcpd[5403]: DHCPDISCOVER from 54:2b:8d:8a:54:79 via
eth0: load balance to
peer dhcp-failover
May 19 11:15:58 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.152 DHCID:
78:3a:84:bc:2c:db Name:
Aarons-iPad
May 19 11:15:58 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:15:58 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:15:58 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.152
May 19 11:15:58 fddc11 dhcpd[5403]: execute_statement argv[3] =
78:3a:84:bc:2c:db
May 19 11:15:58 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPad
May 19 11:15:58 fddc11 sh[5403]: Record deleted successfully
May 19 11:15:59 fddc11 sh[5403]: Record added successfully
May 19 11:16:00 fddc11 sh[5403]: 172.20.10
May 19 11:16:00 fddc11 sh[5403]: 152
May 19 11:16:00 fddc11 sh[5403]: Record deleted successfully
May 19 11:16:01 fddc11 sh[5403]: Record added successfully
May 19 11:16:01 fddc11 dhcpd[2433]: DHCP-DNS Update succeeded
May 19 11:16:02 fddc11 dhcpd[2445]: Computer 'Aarons-iPad' not found.
Exiting.
May 19 11:16:02 fddc11 dhcpd[5403]: execute: /usr/local/bin/dhcp-dyndns.sh exit
status 17408
May 19 11:16:02 fddc11 dhcpd[5403]: reuse_lease: lease age 62 (secs) under 25%
threshold, reply
with unaltered, existing lease for 172.20.10.152
May 19 11:16:02 fddc11 dhcpd[5403]: DHCPREQUEST for 172.20.10.152 from
78:3a:84:bc:2c:db
(Aarons-iPad) via eth0
May 19 11:16:02 fddc11 dhcpd[5403]: DHCPACK on 172.20.10.152 to
78:3a:84:bc:2c:db (Aarons-iPad) via
eth0
May 19 11:16:02 fddc11 dhcpd[5403]: Commit: IP: 172.20.10.152 DHCID:
78:3a:84:bc:2c:db Name:
Aarons-iPad
May 19 11:16:02 fddc11 dhcpd[5403]: execute_statement argv[0] =
/usr/local/bin/dhcp-dyndns.sh
May 19 11:16:02 fddc11 dhcpd[5403]: execute_statement argv[1] = add
May 19 11:16:02 fddc11 dhcpd[5403]: execute_statement argv[2] = 172.20.10.152
May 19 11:16:02 fddc11 dhcpd[5403]: execute_statement argv[3] =
78:3a:84:bc:2c:db
May 19 11:16:02 fddc11 dhcpd[5403]: execute_statement argv[4] = Aarons-iPad
May 19 11:16:02 fddc11 sh[5403]: Record deleted successfully
May 19 11:16:03 fddc11 sh[5403]: Record added successfully
....

When I look in DNS in my Forward Lookup Zone via Windows 10 I have multiple A
Host records with the
same ip address but the names are like this:

Aarons-iPad Host(A) 172.20.10.152 static
Aarons-iPadCNF:134dd19a-e0fd-4230-8108-40b4ae3328d9 Host(A) 172.20.10.152 static
Aarons-iPadCNF:156181c7-c420-409d-ab88-40c56f6b1c88 Host(A) 172.20.10.152 static
..... - currently there are 13 such entries & there are similar records for
other hosts.

The same multiple PTR records are present in the Reverse Lookup Zone.

I followed the samba wiki
https://wiki.samba.org/index.php/Configure_DHCP_to_update_DNS_records_with_BIND9
and have modified
/etc/dhcp/dhcpd.conf as noted in the wiki. I have the dhcp-dyndns.sh script
copied from the wiki. I
did have to add absolute paths for the samba and samba-tool commands as this is
self-compiled and
installed to /usr/local/samba. Also,note that on Ubuntu 18.04 aarch64,
isc-dhcp-server runs as
dhcpd:dhcpd

This seems to be happening with iphone/ipads (wireless) but also HP printers
that are all wired.

Does anybody have any suggestions?

Thanks for any assistance.

Mark

Rowland penny

2020-May-20 09:54 UTC

head link

[Samba] DHCP Updates to DNS - Multiple Entries with Same IP

On 19/05/2020 22:29, Mark Petersen via samba wrote:> I'm having difficulties with dhcpd updating DNS entries.
>
> When I look in DNS in my Forward Lookup Zone via Windows 10 I have multiple
A Host records with the
> same ip address but the names are like this:
>
> Aarons-iPad Host(A) 172.20.10.152 static
> Aarons-iPadCNF:134dd19a-e0fd-4230-8108-40b4ae3328d9 Host(A) 172.20.10.152
static
> Aarons-iPadCNF:156181c7-c420-409d-ab88-40c56f6b1c88 Host(A) 172.20.10.152
staticThe 'CNF' is short for 'collision', multiple things are trying
to update
the record at the same time, first one wins, the rest get marked with 
the 'CNF'.> Also,note that on Ubuntu 18.04 aarch64, isc-dhcp-server runs as
> dhcpd:dhcpdI just found out that Debian 10 now uses 'dhcpd' as well
;-)>
> This seems to be happening with iphone/ipads (wireless) but also HP
printers that are all wired.
It looks like your clients are trying to update their own records, you 
only need the script if some or all of your clients cannot update their 
own records, but, if you use the script, you must stop the clients from 
trying to update their own records.

Rowland

Mark Peteren

2020-May-20 21:44 UTC

head link

[Samba] DHCP Updates to DNS - Multiple Entries with Same IP

On Wed, 2020-05-20 at 10:54 +0100, Rowland penny via samba
wrote:> On 19/05/2020 22:29, Mark Petersen via samba wrote:
> > I'm having difficulties with dhcpd updating DNS entries.
> > 
> > When I look in DNS in my Forward Lookup Zone via Windows 10 I have
> > multiple A Host records with the
> > same ip address but the names are like this:
> > 
> > Aarons-iPad Host(A) 172.20.10.152 static
> > Aarons-iPadCNF:134dd19a-e0fd-4230-8108-40b4ae3328d9 Host(A)
> > 172.20.10.152 static
> > Aarons-iPadCNF:156181c7-c420-409d-ab88-40c56f6b1c88 Host(A)
> > 172.20.10.152 static
> The 'CNF' is short for 'collision', multiple things are
trying to
> update 
> the record at the same time, first one wins, the rest get marked
> with 
> the 'CNF'.
> > Also,note that on Ubuntu 18.04 aarch64, isc-dhcp-server runs as
> > dhcpd:dhcpd
> I just found out that Debian 10 now uses 'dhcpd' as well ;-)
> > This seems to be happening with iphone/ipads (wireless) but also HP
> > printers that are all wired.
> 
> It looks like your clients are trying to update their own records,
> you 
> only need the script if some or all of your clients cannot update
> their 
> own records, but, if you use the script, you must stop the clients
> from 
> trying to update their own records.
> 
> Rowland
> Rowland,

Thanks for the response.

I had the script running on both of the dhcp servers (they are setup
with failover), and I had a lot of thses CNF entries in DNS.

So as a test, I removed the script from fddc11 and the problem with all
of the extra DNS entries has stopped. Hosts are showing up in both DNS
servers as I had hoped. I will run like this for a while and see how it
goes.

Mark

Derek Cramer

2020-May-21 11:22 UTC

head link

[Samba] Fwd: DHCP Updates to DNS - Multiple Entries with Same IP

Forgot to CC the list. Duh.

Regards,
Derek


---------- Forwarded message ---------
From: Derek Cramer <cramerd at gmail.com>
Date: Thu, 21 May 2020 at 12:20
Subject: Re: [Samba] DHCP Updates to DNS - Multiple Entries with Same IP
To: <mark.petersen at markofall.com>


I had exactly the same issue with dual dhcp servers. I solved it by
modifying the script to do conditional updates. I.e. only add the A/PTR
entries if they are not already present.

This works for me, but I have no idea if this is best practice for Active
Directory. I suppose a race condition with simultaneous updates is still
possible, but so far I have no more CNF records. My case is a home network
with <50 dhcp clients, so ymmv.

May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: Commit: IP:
192.168.30.171 DHCID: 3c:18:a0:bf:d4:32 Name: L90WGZG5
May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: execute_statement
argv[0] = /etc/dhcp/scripts/dhcp-dyndns.sh
May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: execute_statement
argv[1] = add
May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: execute_statement
argv[2] = 192.168.30.171
May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: execute_statement
argv[3] = 3c:18:a0:bf:d4:32
May 21 11:24:59 dc1.internal.example.com dhcpd[256642]: execute_statement
argv[4] = L90WGZG5
May 21 11:25:00 dc1.internal.example.com dhcpd[260327]: A record already
exists for L90WGZG5 -> 192.168.30.171
May 21 11:25:00 dc1.internal.example.com dhcpd[260328]: PTR record already
exists for 192.168.30.171 -> L90WGZG5.internal.example.com
May 21 11:25:00 dc1.internal.example.com dhcpd[256642]: DHCPREQUEST for
192.168.30.171 from 3c:18:a0:bf:d4:32 (L90WGZG5) via enp1s0
May 21 11:25:00 dc1.internal.example.com dhcpd[256642]: DHCPACK on
192.168.30.171 to 3c:18:a0:bf:d4:32 (L90WGZG5) via enp1s0



Regards,
Derek


On Wed, 20 May 2020 at 22:46, Mark Peteren via samba <samba at
lists.samba.org>
wrote:
> On Wed, 2020-05-20 at 10:54 +0100, Rowland penny via samba wrote:
> > On 19/05/2020 22:29, Mark Petersen via samba wrote:
> > > I'm having difficulties with dhcpd updating DNS entries.
> > >
> > > When I look in DNS in my Forward Lookup Zone via Windows 10 I
have
> > > multiple A Host records with the
> > > same ip address but the names are like this:
> > >
> > > Aarons-iPad Host(A) 172.20.10.152 static
> > > Aarons-iPadCNF:134dd19a-e0fd-4230-8108-40b4ae3328d9 Host(A)
> > > 172.20.10.152 static
> > > Aarons-iPadCNF:156181c7-c420-409d-ab88-40c56f6b1c88 Host(A)
> > > 172.20.10.152 static
> > The 'CNF' is short for 'collision', multiple things
are trying to
> > update
> > the record at the same time, first one wins, the rest get marked
> > with
> > the 'CNF'.
> > > Also,note that on Ubuntu 18.04 aarch64, isc-dhcp-server runs as
> > > dhcpd:dhcpd
> > I just found out that Debian 10 now uses 'dhcpd' as well ;-)
> > > This seems to be happening with iphone/ipads (wireless) but also
HP
> > > printers that are all wired.
> >
> > It looks like your clients are trying to update their own records,
> > you
> > only need the script if some or all of your clients cannot update
> > their
> > own records, but, if you use the script, you must stop the clients
> > from
> > trying to update their own records.
> >
> > Rowland
> >
> Rowland,
>
> Thanks for the response.
>
> I had the script running on both of the dhcp servers (they are setup
> with failover), and I had a lot of thses CNF entries in DNS.
>
> So as a test, I removed the script from fddc11 and the problem with all
> of the extra DNS entries has stopped. Hosts are showing up in both DNS
> servers as I had hoped. I will run like this for a while and see how it
> goes.
>
> Mark
>
>
> --
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/options/samba
>

Rowland penny

2020-May-21 12:07 UTC

head link

[Samba] Fwd: DHCP Updates to DNS - Multiple Entries with Same IP

On 21/05/2020 12:22, Derek Cramer via samba wrote:> I had exactly the same issue with dual dhcp servers. I solved it by
> modifying the script to do conditional updates. I.e. only add the A/PTR
> entries if they are not already present.
Now that is a good idea, why didn't I think of it ;-)

I have identified a slight bug with the 'add' part, if you reboot a 
client and it releases the IP, then when the the client comes up and the 
script is run, it claims the update has failed, even though it has 
succeeded. I have a fix.

The problem with the 'failover' is down to using '128' on both
DC's,
this leads to both of them replying to requests, I will update the 
wikipage to use '255' on the primary and '0' on the secondary.
This
should lead to only one (the primary) replying unless the primary goes down.

Rowland

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