source4/scripting/bin/samba_upgradedns

   1 #!/usr/bin/env python3
   2 #
   3 # Unix SMB/CIFS implementation.
   4 # Copyright (C) Amitay Isaacs <amitay@gmail.com> 2012
   5 #
   6 # Upgrade DNS provision from BIND9_FLATFILE to BIND9_DLZ or SAMBA_INTERNAL
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 3 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20
  21 import sys
  22 import os
  23 import errno
  24 import optparse
  25 import logging
  26 import grp
  27 from base64 import b64encode
  28 import shlex
  29
  30 sys.path.insert(0, "bin/python")
  31
  32 import ldb
  33 import samba
  34 from samba import param
  35 from samba.auth import system_session
  36 from samba.ndr import (
  37     ndr_pack,
  38     ndr_unpack )
  39 import samba.getopt as options
  40 from samba.upgradehelpers import (
  41     get_paths,
  42     get_ldbs )
  43 from samba.dsdb import DS_DOMAIN_FUNCTION_2003
  44 from samba.provision import (
  45     find_provision_key_parameters,
  46     interface_ips_v4,
  47     interface_ips_v6 )
  48 from samba.provision.common import (
  49     setup_path,
  50     setup_add_ldif,
  51     FILL_FULL)
  52 from samba.provision.sambadns import (
  53     ARecord,
  54     AAAARecord,
  55     CNAMERecord,
  56     NSRecord,
  57     SOARecord,
  58     SRVRecord,
  59     TXTRecord,
  60     get_dnsadmins_sid,
  61     add_dns_accounts,
  62     create_dns_partitions,
  63     fill_dns_data_partitions,
  64     create_dns_dir,
  65     secretsdb_setup_dns,
  66     create_dns_dir_keytab_link,
  67     create_samdb_copy,
  68     create_named_conf,
  69     create_named_txt )
  70 from samba.dcerpc import security
  71
  72 import dns.zone, dns.rdatatype
  73
  74 __docformat__ = 'restructuredText'
  75
  76
  77 def find_bind_gid():
  78     """Find system group id for bind9
  79     """
  80     for name in ["bind", "named"]:
  81         try:
  82             return grp.getgrnam(name)[2]
  83         except KeyError:
  84             pass
  85     return None
  86
  87
  88 def convert_dns_rdata(rdata, serial=1):
  89     """Convert resource records in dnsRecord format
  90     """
  91     if rdata.rdtype == dns.rdatatype.A:
  92         rec = ARecord(rdata.address, serial=serial)
  93     elif rdata.rdtype == dns.rdatatype.AAAA:
  94         rec = AAAARecord(rdata.address, serial=serial)
  95     elif rdata.rdtype == dns.rdatatype.CNAME:
  96         rec = CNAMERecord(rdata.target.to_text(), serial=serial)
  97     elif rdata.rdtype == dns.rdatatype.NS:
  98         rec = NSRecord(rdata.target.to_text(), serial=serial)
  99     elif rdata.rdtype == dns.rdatatype.SRV:
 100         rec = SRVRecord(rdata.target.to_text(), int(rdata.port),
 101                         priority=int(rdata.priority), weight=int(rdata.weight),
 102                         serial=serial)
 103     elif rdata.rdtype == dns.rdatatype.TXT:
 104         slist = shlex.split(rdata.to_text())
 105         rec = TXTRecord(slist, serial=serial)
 106     elif rdata.rdtype == dns.rdatatype.SOA:
 107         rec = SOARecord(rdata.mname.to_text(), rdata.rname.to_text(),
 108                         serial=int(rdata.serial),
 109                         refresh=int(rdata.refresh), retry=int(rdata.retry),
 110                         expire=int(rdata.expire), minimum=int(rdata.minimum))
 111     else:
 112         rec = None
 113     return rec
 114
 115
 116 def import_zone_data(samdb, logger, zone, serial, domaindn, forestdn,
 117                      dnsdomain, dnsforest):
 118     """Insert zone data in DNS partitions
 119     """
 120     labels = dnsdomain.split('.')
 121     labels.append('')
 122     domain_root = dns.name.Name(labels)
 123     domain_prefix = "DC=%s,CN=MicrosoftDNS,DC=DomainDnsZones,%s" % (dnsdomain,
 124                                                                     domaindn)
 125
 126     tmp = "_msdcs.%s" % dnsforest
 127     labels = tmp.split('.')
 128     labels.append('')
 129     forest_root = dns.name.Name(labels)
 130     dnsmsdcs = "_msdcs.%s" % dnsforest
 131     forest_prefix = "DC=%s,CN=MicrosoftDNS,DC=ForestDnsZones,%s" % (dnsmsdcs,
 132                                                                     forestdn)
 133
 134     # Extract @ record
 135     at_record = zone.get_node(domain_root)
 136     zone.delete_node(domain_root)
 137
 138     # SOA record
 139     rdset = at_record.get_rdataset(dns.rdataclass.IN, dns.rdatatype.SOA)
 140     soa_rec = ndr_pack(convert_dns_rdata(rdset[0]))
 141     at_record.delete_rdataset(dns.rdataclass.IN, dns.rdatatype.SOA)
 142
 143     # NS record
 144     rdset = at_record.get_rdataset(dns.rdataclass.IN, dns.rdatatype.NS)
 145     ns_rec = ndr_pack(convert_dns_rdata(rdset[0]))
 146     at_record.delete_rdataset(dns.rdataclass.IN, dns.rdatatype.NS)
 147
 148     # A/AAAA records
 149     ip_recs = []
 150     for rdset in at_record:
 151         for r in rdset:
 152             rec = convert_dns_rdata(r)
 153             ip_recs.append(ndr_pack(rec))
 154
 155     # Add @ record for domain
 156     dns_rec = [soa_rec, ns_rec] + ip_recs
 157     msg = ldb.Message(ldb.Dn(samdb, 'DC=@,%s' % domain_prefix))
 158     msg["objectClass"] = ["top", "dnsNode"]
 159     msg["dnsRecord"] = ldb.MessageElement(dns_rec, ldb.FLAG_MOD_ADD,
 160                                           "dnsRecord")
 161     try:
 162         samdb.add(msg)
 163     except Exception:
 164         logger.error("Failed to add @ record for domain")
 165         raise
 166     logger.debug("Added @ record for domain")
 167
 168     # Add @ record for forest
 169     dns_rec = [soa_rec, ns_rec]
 170     msg = ldb.Message(ldb.Dn(samdb, 'DC=@,%s' % forest_prefix))
 171     msg["objectClass"] = ["top", "dnsNode"]
 172     msg["dnsRecord"] = ldb.MessageElement(dns_rec, ldb.FLAG_MOD_ADD,
 173                                           "dnsRecord")
 174     try:
 175         samdb.add(msg)
 176     except Exception:
 177         logger.error("Failed to add @ record for forest")
 178         raise
 179     logger.debug("Added @ record for forest")
 180
 181     # Add remaining records in domain and forest
 182     for node in zone.nodes:
 183         name = node.relativize(forest_root).to_text()
 184         if name == node.to_text():
 185             name = node.relativize(domain_root).to_text()
 186             dn = "DC=%s,%s" % (name, domain_prefix)
 187             fqdn = "%s.%s" % (name, dnsdomain)
 188         else:
 189             dn = "DC=%s,%s" % (name, forest_prefix)
 190             fqdn = "%s.%s" % (name, dnsmsdcs)
 191
 192         dns_rec = []
 193         for rdataset in zone.nodes[node]:
 194             for rdata in rdataset:
 195                 rec = convert_dns_rdata(rdata, serial)
 196                 if not rec:
 197                     logger.warn("Unsupported record type (%s) for %s, ignoring" %
 198                                 dns.rdatatype.to_text(rdata.rdatatype), name)
 199                 else:
 200                     dns_rec.append(ndr_pack(rec))
 201
 202         msg = ldb.Message(ldb.Dn(samdb, dn))
 203         msg["objectClass"] = ["top", "dnsNode"]
 204         msg["dnsRecord"] = ldb.MessageElement(dns_rec, ldb.FLAG_MOD_ADD,
 205                                               "dnsRecord")
 206         try:
 207             samdb.add(msg)
 208         except Exception:
 209             logger.error("Failed to add DNS record %s" % (fqdn))
 210             raise
 211         logger.debug("Added DNS record %s" % (fqdn))
 212
 213 def cleanup_remove_file(file_path):
 214     try:
 215         os.remove(file_path)
 216     except OSError as e:
 217         if e.errno not in [errno.EEXIST, errno.ENOENT]:
 218             pass
 219         else:
 220             logger.debug("Could not remove %s: %s" % (file_path, e.strerror))
 221
 222 def cleanup_remove_dir(dir_path):
 223     try:
 224         for root, dirs, files in os.walk(dir_path, topdown=False):
 225             for name in files:
 226                 os.remove(os.path.join(root, name))
 227             for name in dirs:
 228                 os.rmdir(os.path.join(root, name))
 229         os.rmdir(dir_path)
 230     except OSError as e:
 231         if e.errno not in [errno.EEXIST, errno.ENOENT]:
 232             pass
 233         else:
 234             logger.debug("Could not delete dir %s: %s" % (dir_path, e.strerror))
 235
 236 def cleanup_obsolete_dns_files(paths):
 237     cleanup_remove_file(os.path.join(paths.private_dir, "named.conf"))
 238     cleanup_remove_file(os.path.join(paths.private_dir, "named.conf.update"))
 239     cleanup_remove_file(os.path.join(paths.private_dir, "named.txt"))
 240
 241     cleanup_remove_dir(os.path.join(paths.private_dir, "dns"))
 242
 243
 244 # dnsprovision creates application partitions for AD based DNS mainly if the existing
 245 # provision was created using earlier snapshots of samba4 which did not have support
 246 # for DNS partitions
 247
 248 if __name__ == '__main__':
 249
 250     # Setup command line parser
 251     parser = optparse.OptionParser("samba_upgradedns [options]")
 252     sambaopts = options.SambaOptions(parser)
 253     credopts = options.CredentialsOptions(parser)
 254
 255     parser.add_option_group(options.VersionOptions(parser))
 256     parser.add_option_group(sambaopts)
 257     parser.add_option_group(credopts)
 258
 259     parser.add_option("--dns-backend", type="choice", metavar="<BIND9_DLZ|SAMBA_INTERNAL>",
 260                       choices=["SAMBA_INTERNAL", "BIND9_DLZ"], default="SAMBA_INTERNAL",
 261                       help="The DNS server backend, default SAMBA_INTERNAL")
 262     parser.add_option("--migrate", type="choice", metavar="<yes|no>",
 263                       choices=["yes","no"], default="yes",
 264                       help="Migrate existing zone data, default yes")
 265     parser.add_option("--verbose", help="Be verbose", action="store_true")
 266
 267     opts = parser.parse_args()[0]
 268
 269     if opts.dns_backend is None:
 270         opts.dns_backend = 'SAMBA_INTERNAL'
 271
 272     if opts.migrate:
 273         autofill = False
 274     else:
 275         autofill = True
 276
 277     # Set up logger
 278     logger = logging.getLogger("upgradedns")
 279     logger.addHandler(logging.StreamHandler(sys.stdout))
 280     logger.setLevel(logging.INFO)
 281     if opts.verbose:
 282         logger.setLevel(logging.DEBUG)
 283
 284     lp = sambaopts.get_loadparm()
 285     lp.load(lp.configfile)
 286     creds = credopts.get_credentials(lp)
 287
 288     logger.info("Reading domain information")
 289     paths = get_paths(param, smbconf=lp.configfile)
 290     paths.bind_gid = find_bind_gid()
 291     ldbs = get_ldbs(paths, creds, system_session(), lp)
 292     names = find_provision_key_parameters(ldbs.sam, ldbs.secrets, ldbs.idmap,
 293                                            paths, lp.configfile, lp)
 294
 295     if names.domainlevel < DS_DOMAIN_FUNCTION_2003:
 296         logger.error("Cannot create AD based DNS for OS level < 2003")
 297         sys.exit(1)
 298
 299     domaindn = names.domaindn
 300     forestdn = names.rootdn
 301
 302     dnsdomain = names.dnsdomain.lower()
 303     dnsforest = dnsdomain
 304
 305     site = names.sitename
 306     hostname = names.hostname
 307     dnsname = '%s.%s' % (hostname, dnsdomain)
 308
 309     domainsid = names.domainsid
 310     domainguid = names.domainguid
 311     ntdsguid = names.ntdsguid
 312
 313     # Check for DNS accounts and create them if required
 314     try:
 315         msg = ldbs.sam.search(base=domaindn, scope=ldb.SCOPE_DEFAULT,
 316                               expression='(sAMAccountName=DnsAdmins)',
 317                               attrs=['objectSid'])
 318         dnsadmins_sid = ndr_unpack(security.dom_sid, msg[0]['objectSid'][0])
 319     except IndexError:
 320         logger.info("Adding DNS accounts")
 321         add_dns_accounts(ldbs.sam, domaindn)
 322         dnsadmins_sid = get_dnsadmins_sid(ldbs.sam, domaindn)
 323     else:
 324         logger.info("DNS accounts already exist")
 325
 326     # Import dns records from zone file
 327     if os.path.exists(paths.dns):
 328         logger.info("Reading records from zone file %s" % paths.dns)
 329         try:
 330             zone = dns.zone.from_file(paths.dns, relativize=False)
 331             rrset = zone.get_rdataset("%s." % dnsdomain, dns.rdatatype.SOA)
 332             serial = int(rrset[0].serial)
 333         except Exception as e:
 334             logger.warn("Error parsing DNS data from '%s' (%s)" % (paths.dns, str(e)))
 335             autofill = True
 336     else:
 337         logger.info("No zone file %s (normal)" % paths.dns)
 338         autofill = True
 339
 340     # Create DNS partitions if missing and fill DNS information
 341     try:
 342         expression = '(|(dnsRoot=DomainDnsZones.%s)(dnsRoot=ForestDnsZones.%s))' % \
 343                      (dnsdomain, dnsforest)
 344         msg = ldbs.sam.search(base=names.configdn, scope=ldb.SCOPE_DEFAULT,
 345                               expression=expression, attrs=['nCName'])
 346         ncname = msg[0]['nCName'][0]
 347     except IndexError:
 348         logger.info("Creating DNS partitions")
 349
 350         logger.info("Looking up IPv4 addresses")
 351         hostip = interface_ips_v4(lp)
 352         try:
 353             hostip.remove('127.0.0.1')
 354         except ValueError:
 355             pass
 356         if not hostip:
 357             logger.error("No IPv4 addresses found")
 358             sys.exit(1)
 359         else:
 360             hostip = hostip[0]
 361             logger.debug("IPv4 addresses: %s" % hostip)
 362
 363         logger.info("Looking up IPv6 addresses")
 364         hostip6 = interface_ips_v6(lp)
 365         if not hostip6:
 366             hostip6 = None
 367         else:
 368             hostip6 = hostip6[0]
 369         logger.debug("IPv6 addresses: %s" % hostip6)
 370
 371         create_dns_partitions(ldbs.sam, domainsid, names, domaindn, forestdn,
 372                               dnsadmins_sid, FILL_FULL)
 373
 374         logger.info("Populating DNS partitions")
 375         if autofill:
 376             logger.warn("DNS records will be automatically created")
 377
 378         fill_dns_data_partitions(ldbs.sam, domainsid, site, domaindn, forestdn,
 379                              dnsdomain, dnsforest, hostname, hostip, hostip6,
 380                              domainguid, ntdsguid, dnsadmins_sid,
 381                              autofill=autofill)
 382
 383         if not autofill:
 384             logger.info("Importing records from zone file")
 385             import_zone_data(ldbs.sam, logger, zone, serial, domaindn, forestdn,
 386                              dnsdomain, dnsforest)
 387     else:
 388         logger.info("DNS partitions already exist")
 389
 390     # Mark that we are hosting DNS partitions
 391     try:
 392         dns_nclist = [ 'DC=DomainDnsZones,%s' % domaindn,
 393                        'DC=ForestDnsZones,%s' % forestdn ]
 394
 395         msgs = ldbs.sam.search(base=names.serverdn, scope=ldb.SCOPE_DEFAULT,
 396                                expression='(objectclass=nTDSDSa)',
 397                                attrs=['hasPartialReplicaNCs',
 398                                       'msDS-hasMasterNCs'])
 399         msg = msgs[0]
 400
 401         master_nclist = []
 402         ncs = msg.get("msDS-hasMasterNCs")
 403         if ncs:
 404             for nc in ncs:
 405                 master_nclist.append(str(nc))
 406
 407         partial_nclist = []
 408         ncs = msg.get("hasPartialReplicaNCs")
 409         if ncs:
 410             for nc in ncs:
 411                 partial_nclist.append(str(nc))
 412
 413         modified_master = False
 414         modified_partial = False
 415
 416         for nc in dns_nclist:
 417             if nc not in master_nclist:
 418                 master_nclist.append(nc)
 419                 modified_master = True
 420             if nc in partial_nclist:
 421                 partial_nclist.remove(nc)
 422                 modified_partial = True
 423
 424         if modified_master or modified_partial:
 425             logger.debug("Updating msDS-hasMasterNCs and hasPartialReplicaNCs attributes")
 426             m = ldb.Message()
 427             m.dn = msg.dn
 428             if modified_master:
 429                 m["msDS-hasMasterNCs"] = ldb.MessageElement(master_nclist,
 430                                                             ldb.FLAG_MOD_REPLACE,
 431                                                             "msDS-hasMasterNCs")
 432             if modified_partial:
 433                 if partial_nclist:
 434                     m["hasPartialReplicaNCs"] = ldb.MessageElement(partial_nclist,
 435                                                                    ldb.FLAG_MOD_REPLACE,
 436                                                                    "hasPartialReplicaNCs")
 437                 else:
 438                     m["hasPartialReplicaNCs"] = ldb.MessageElement(ncs,
 439                                                                    ldb.FLAG_MOD_DELETE,
 440                                                                    "hasPartialReplicaNCs")
 441             ldbs.sam.modify(m)
 442     except Exception:
 443         raise
 444
 445     # Special stuff for DLZ backend
 446     if opts.dns_backend == "BIND9_DLZ":
 447         config_migration = False
 448
 449         if (paths.private_dir != paths.binddns_dir and
 450             os.path.isfile(os.path.join(paths.private_dir, "named.conf"))):
 451             config_migration = True
 452
 453         # Check if dns-HOSTNAME account exists and create it if required
 454         secrets_msgs = ldbs.secrets.search(expression='(samAccountName=dns-%s)' % hostname, attrs=['secret'])
 455         msg = ldbs.sam.search(base=domaindn, scope=ldb.SCOPE_DEFAULT,
 456                               expression='(sAMAccountName=dns-%s)' % (hostname),
 457                               attrs=[])
 458
 459         if len(secrets_msgs) == 0 or len(msg) == 0:
 460             logger.info("Adding dns-%s account" % hostname)
 461
 462             if len(secrets_msgs) == 1:
 463                 dn = secrets_msgs[0].dn
 464                 ldbs.secrets.delete(dn)
 465
 466             if len(msg) == 1:
 467                 dn = msg[0].dn
 468                 ldbs.sam.delete(dn)
 469
 470             dnspass = samba.generate_random_password(128, 255)
 471             setup_add_ldif(ldbs.sam, setup_path("provision_dns_add_samba.ldif"), {
 472                     "DNSDOMAIN": dnsdomain,
 473                     "DOMAINDN": domaindn,
 474                     "DNSPASS_B64": b64encode(dnspass.encode('utf-16-le')).decode('utf8'),
 475                     "HOSTNAME" : hostname,
 476                     "DNSNAME" : dnsname }
 477                            )
 478
 479             res = ldbs.sam.search(base=domaindn, scope=ldb.SCOPE_DEFAULT,
 480                                   expression='(sAMAccountName=dns-%s)' % (hostname),
 481                                   attrs=["msDS-KeyVersionNumber"])
 482             if "msDS-KeyVersionNumber" in res[0]:
 483                 dns_key_version_number = int(res[0]["msDS-KeyVersionNumber"][0])
 484             else:
 485                 dns_key_version_number = None
 486
 487             secretsdb_setup_dns(ldbs.secrets, names,
 488                                 paths.private_dir, paths.binddns_dir, realm=names.realm,
 489                                 dnsdomain=names.dnsdomain,
 490                                 dns_keytab_path=paths.dns_keytab, dnspass=dnspass,
 491                                 key_version_number=dns_key_version_number)
 492
 493         else:
 494             logger.info("dns-%s account already exists" % hostname)
 495
 496         if not os.path.exists(paths.binddns_dir):
 497             # This directory won't exist if we're restoring from an offline backup.
 498             os.mkdir(paths.binddns_dir, 0o770)
 499
 500         create_dns_dir_keytab_link(logger, paths)
 501
 502         # This forces a re-creation of dns directory and all the files within
 503         # It's an overkill, but it's easier to re-create a samdb copy, rather
 504         # than trying to fix a broken copy.
 505         create_dns_dir(logger, paths)
 506
 507         # Setup a copy of SAM for BIND9
 508         create_samdb_copy(ldbs.sam, logger, paths, names, domainsid,
 509                           domainguid)
 510
 511         create_named_conf(paths, names.realm, dnsdomain, opts.dns_backend, logger)
 512
 513         create_named_txt(paths.namedtxt, names.realm, dnsdomain, dnsname,
 514                          paths.binddns_dir, paths.dns_keytab)
 515
 516         cleanup_obsolete_dns_files(paths)
 517
 518         if config_migration:
 519             logger.info("ATTENTION: The BIND configuration and keytab has been moved to: %s",
 520                         paths.binddns_dir)
 521             logger.info("           Please update your BIND configuration accordingly.")
 522         else:
 523             logger.info("See %s for an example configuration include file for BIND", paths.namedconf)
 524             logger.info("and %s for further documentation required for secure DNS "
 525                         "updates", paths.namedtxt)
 526
 527     elif opts.dns_backend == "SAMBA_INTERNAL":
 528         # Make sure to remove everything from the bind-dns directory to avoid
 529         # possible security issues with the named group having write access
 530         # to all AD partitions
 531         cleanup_remove_file(os.path.join(paths.binddns_dir, "dns.keytab"))
 532         cleanup_remove_file(os.path.join(paths.binddns_dir, "named.conf"))
 533         cleanup_remove_file(os.path.join(paths.binddns_dir, "named.conf.update"))
 534         cleanup_remove_file(os.path.join(paths.binddns_dir, "named.txt"))
 535
 536         cleanup_remove_dir(os.path.dirname(paths.dns))
 537
 538         try:
 539             os.chmod(paths.private_dir, 0o700)
 540             os.chown(paths.private_dir, -1, 0)
 541         except:
 542             logger.warn("Failed to restore owner and permissions for %s",
 543                         (paths.private_dir))
 544
 545         # Check if dns-HOSTNAME account exists and delete it if required
 546         try:
 547             dn_str = 'samAccountName=dns-%s,CN=Principals' % hostname
 548             msg = ldbs.secrets.search(expression='(dn=%s)' % dn_str, attrs=[])
 549             dn = msg[0].dn
 550         except IndexError:
 551             dn = None
 552
 553         if dn is not None:
 554             try:
 555                 ldbs.secrets.delete(dn)
 556             except Exception:
 557                 logger.info("Failed to delete %s from secrets.ldb" % dn)
 558
 559         try:
 560             msg = ldbs.sam.search(base=domaindn, scope=ldb.SCOPE_DEFAULT,
 561                                   expression='(sAMAccountName=dns-%s)' % (hostname),
 562                                   attrs=[])
 563             dn = msg[0].dn
 564         except IndexError:
 565             dn = None
 566
 567         if dn is not None:
 568             try:
 569                 ldbs.sam.delete(dn)
 570             except Exception:
 571                 logger.info("Failed to delete %s from sam.ldb" % dn)
 572
 573     logger.info("Finished upgrading DNS")
 574
 575     services = lp.get("server services")
 576     for service in services:
 577         if service == "dns":
 578             if opts.dns_backend.startswith("BIND"):
 579                 logger.info("You have switched to using %s as your dns backend,"
 580                         " but still have the internal dns starting. Please"
 581                         " make sure you add '-dns' to your server services"
 582                         " line in your smb.conf." % opts.dns_backend)
 583             break
 584     else:
 585         if opts.dns_backend == "SAMBA_INTERNAL":
 586             logger.info("You have switched to using %s as your dns backend,"
 587                     " but you still have samba starting looking for a"
 588                     " BIND backend. Please remove the -dns from your"
 589                     " server services line." % opts.dns_backend)