[Samba] DNS update fails after samba domain controller is restarted
Hoefle, Marco (Avnet Silica)
Marco.Hoefle at avnet.eu
Fri Dec 6 07:18:32 UTC 2024
Hello,
first, after provisioning everything looks ok.
After a restart the samba server wants to update internal DNS records and this fails:
samba | /usr/sbin/samba_dnsupdate: ERROR(runtime): Record already exists; record could not be added. zone[fffff.yyy] name[_ldap._tcp.Default-First-Site-Name._sites.ForestDnsZones] [WERR_DNS_ERROR_RECORD_ALREADY_EXISTS] - (9711, 'WERR_DNS_ERROR_RECORD_ALREADY_EXISTS')
samba | /usr/sbin/samba_dnsupdate: Failed to get Kerberos credentials, falling back to samba-tool: kinit for DC$@fffff.yyy failed (Cannot contact any KDC for requested realm)
samba | /usr/sbin/samba_dnsupdate:
samba | /usr/sbin/samba_dnsupdate: Failed update of 29 entries
samba | dnsupdate_nameupdate_done: Failed DNS update with exit code 29
DNS updates of joined clients do work though:
root at dc:/# tail /var/log/bind/ddns.log -f
06-Dec-2024 08:11:43.249 update: info: client @0x70c94cea97b8 10.3.0.6#34593/key SAMBA-SRV\$\@fffff.yyy: updating zone 'fffff.yyy/NONE': deleting rrset at 'samba-srv.fffff.yyy' A
06-Dec-2024 08:11:43.251 update: info: client @0x70c94cea97b8 10.3.0.6#34593/key SAMBA-SRV\$\@fffff.yyy: updating zone 'fffff.yyy/NONE': adding an RR at 'samba-srv.fffff.yyy' A 10.3.0.6
06-Dec-2024 08:11:43.279 update: info: client @0x70c94cea97b8 10.3.0.6#33953/key SAMBA-SRV\$\@fffff.yyy: updating zone 'fffff.yyy/NONE': deleting rrset at 'samba-srv.fffff.yyy' AAAA
I am using bind as back-end:
samba-ad-dc 2:4.19.5+dfsg-4ubuntu9
bind9 1:9.18.28-0ubuntu0.24.04.1
root at dc:/# cat /etc/samba/smb.conf
# Global parameters
[global]
ldap server require strong auth = no
bind interfaces only = yes
interfaces = eth0
log file = /var/log/samba/log.%m
log level = 2 auth_json_audit:3@/var/log/samba/domain_join.log auth:2@/var/log/samba/auth.log passdb:2 rpc_srv:2 rpc_parse:2
allow dns updates = nonsecure and secure
template homedir = /home/%U
template shell = /bin/bash
rpc server dynamic port range = 49152-65535
winbind nss info = rfc2307
wins support = yes
netbios name = DC
realm = fffff.yyy
server role = active directory domain controller
server services = s3fs, rpc, nbt, wrepl, ldap, cldap, kdc, drepl, winbindd, ntp_signd, kcc, dnsupdate
workgroup = fffff
idmap_ldb:use rfc2307 = yes
[sysvol]
path = /var/lib/samba/sysvol
read only = No
[netlogon]
path = /var/lib/samba/sysvol/fffff.yyy/scripts
read only = No
root at dc:/# cat /etc/named.conf
acl local-networks {
127.0.0.0/8;
172.17.0.0/24;
10.3.0.0/24;
};
options {
directory "/var/named";
pid-file "/run/named/named.pid";
session-keyfile "/run/named/session.key";
allow-query { local-networks; };
allow-recursion { local-networks; };
allow-query-cache { local-networks; };
allow-transfer { local-networks; };
allow-update { local-networks; };
version none;
hostname none;
server-id none;
auth-nxdomain yes;
datasize default;
empty-zones-enable no;
tkey-gssapi-keytab "/var/lib/samba/bind-dns/dns.keytab";
minimal-responses yes;
forwarders { 8.8.8.8; };
listen-on-v6 { none; };
};
include "/var/lib/samba/bind-dns/named.conf";
# dlz "AD DNS Zones" {
# database "dlopen /usr/lib/samba/bind9/dlz_bind9_16.so";
# };
logging {
channel default_log {
file "/var/log/bind/defaut.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel auth_servers_log {
file "/var/log/bind/auth_servers.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel dnssec_log {
file "/var/log/bind/dnssec.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel zone_transfers_log {
file "/var/log/bind/zone_transfers.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel ddns_log {
file "/var/log/bind/ddns.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel client_security_log {
file "/var/log/bind/client_security.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel rate_limiting_log {
file "/var/log/bind/rate_limiting.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel rpz_log {
file "/var/log/bind/rpz.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
channel dnstap_log {
file "/var/log/bind/dnstap.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
//
// If you have the category ‘queries’ defined, and you don’t want query logging
// by default, make sure you add option ‘querylog no;’ - then you can toggle
// query logging on (and off again) using command ‘rndc querylog’
//
channel queries_log {
file "/var/log/bind/queries.log" versions 10 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity info;
};
//
// This channel is dynamic so that when the debug level is increased using
// rndc while the server is running, extra information will be logged about
// failing queries. Other debug information for other categories will be
// sent to the channel default_debug (which is also dynamic), but without
// affecting the regular logging.
//
channel query-errors_log {
file "/var/log/bind/query-errors.log" versions 3 size 20m;
print-time yes;
print-category yes;
print-severity yes;
severity dynamic;
};
//
// This is the default syslog channel, defined here for clarity. You don’t
// have to use it if you prefer to log to your own channels.
// It sends to syslog’s daemon facility, and sends only logged messages
// of priority info and higher.
// (The options to print time, category and severity are non-default.)
//
channel default_syslog {
print-time yes;
print-category yes;
print-severity yes;
syslog daemon;
severity info;
};
//
// This is the default debug output channel, defined here for clarity. You
// might want to redefine the output destination if it doesn’t fit with your
// local system administration plans for logging. It is also a special
// channel that only produces output if the debug level is non-zero.
//
channel default_debug {
print-time yes;
print-category yes;
print-severity yes;
file "/var/log/bind/debug.log";
severity dynamic;
};
//
// Log routine stuff to syslog and default log:
//
category default { default_syslog; default_debug; default_log; };
category config { default_syslog; default_debug; default_log; };
category dispatch { default_syslog; default_debug; default_log; };
category network { default_syslog; default_debug; default_log; };
category general { default_syslog; default_debug; default_log; };
//
// From BIND 9.12 and newer, you can direct zone load logging to another
// channel with the new zoneload logging category. If this would be useful
// then firstly, configure the new channel, and then edit the line below
// to direct the category there instead of to syslog and default log:
//
category zoneload { default_syslog; default_debug; default_log; };
//
// Log messages relating to what we got back from authoritative servers during
// recursion (if lame-servers and edns-disabled are obscuring other messages
// they can be sent to their own channel or to null). Sometimes these log
// messages will be useful to research why some domains don’t resolve or
// don’t resolve reliably
//
category resolver { auth_servers_log; default_debug; };
category cname { auth_servers_log; default_debug; };
category delegation-only { auth_servers_log; default_debug; };
category lame-servers { auth_servers_log; default_debug; };
category edns-disabled { auth_servers_log; default_debug; };
//
// Log problems with DNSSEC:
//
category dnssec { dnssec_log; default_debug; };
//
// Log together all messages relating to authoritative zone propagation
//
category notify { zone_transfers_log; default_debug; };
category xfer-in { zone_transfers_log; default_debug; };
category xfer-out { zone_transfers_log; default_debug; };
//
// Log together all messages relating to dynamic updates to DNS zone data:
//
category update{ ddns_log; default_debug; };
category update-security { ddns_log; default_debug; };
//
// Log together all messages relating to client access and security.
// (There is an additional category ‘unmatched’ that is by default sent to
// null but which can be added here if you want more than the one-line
// summary that is logged for failures to match a view).
//
category client{ client_security_log; default_debug; };
category security { client_security_log; default_debug; };
//
// Log together all messages that are likely to be related to rate-limiting.
// This includes RRL (Response Rate Limiting) - usually deployed on authoritative
// servers and fetches-per-server|zone. Note that it does not include
// logging of changes for clients-per-query (which are logged in category
// resolver). Also note that there may on occasions be other log messages
// emitted by the database category that don’t relate to rate-limiting
// behaviour by named.
//
category rate-limit { rate_limiting_log; default_debug; };
category spill { rate_limiting_log; default_debug; };
category database { rate_limiting_log; default_debug; };
//
// Log DNS-RPZ (Response Policy Zone) messages (if you are not using DNS-RPZ
// then you may want to comment out this category and associated channel)
//
category rpz { rpz_log; default_debug; };
//
// Log messages relating to the "dnstap" DNS traffic capture system (if you
// are not using dnstap, then you may want to comment out this category and
// associated channel).
//
category dnstap { dnstap_log; default_debug; };
//
// If you are running a server (for example one of the Internet root
// nameservers) that is providing RFC 5011 trust anchor updates, then you
// may be interested in logging trust anchor telemetry reports that your
// server receives to analyze anchor propagation rates during a key rollover.
// If this would be useful then firstly, configure the new channel, and then
// un-comment and the line below to direct the category there instead of to
// syslog and default log:
//
//
category trust-anchor-telemetry { default_syslog; default_debug; default_log; };
//
// If you have the category ‘queries’ defined, and you don’t want query logging
// by default, make sure you add option ‘querylog no;’ - then you can toggle
// query logging on (and off again) using command ‘rndc querylog’
//
category queries { queries_log; };
//
// This logging category will only emit messages at debug levels of 1 or
// higher - it can be useful to troubleshoot problems where queries are
// resulting in a SERVFAIL response.
//
category query-errors {query-errors_log; };
};
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