Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Apple > Operating Systems

  • Print
  • + Share This
This chapter is from the book

Troubleshooting Binding Issues

For the most part, binding to Active Directory should just work. Some conditions, however, will prevent binding. This section introduces potential problem areas and provides instructions on how to resolve them.

Using Command-Line Tools to Confirm Binding

You can confirm that you are bound to Active Directory with the dsconfigad -show command and option, which also shows the status of many Active Directory plug-in options. You can also use the dscl or id commands to confirm that Mac OS X is bound to Active Directory. For example:

client17:~ cadmin$ dsconfigad -show
cadmin's Password: [password typed but hidden]
You are bound to Active Directory:
  Active Directory Forest        =
  Active Directory Domain        =
  Computer Account               = client17
Advanced Options - User Experience
  Create mobile account at login = Disabled
     Require confirmation        = Enabled
  Force home to startup disk     = Enabled
  Use Windows UNC path for home  = Disabled
     Network protocol to be used = smb:
  Default user Shell             = /bin/bash
Advanced Options - Mappings
  Mapping UID to attribute       = not set
  Mapping user GID to attribute  = not set
  Mapping group GID to attribute = not set
Advanced Options - Administrative
  Preferred Domain controller    = not set
  Allowed admin groups           = not set
  Authentication from any domain = Enabled
  Packet signing                 = allow
  Packet encryption              = allow
Advanced Options - Static maps
client17:~ cadmin$ dscl /Active\ Directory/All\ Domains \
-list /Users
[a successful bind will display a list of users; not shown here]
client17:~ cadmin$ id -p aduser1
uid aduser1
groups       AD\domain users

Binding After Imaging

If you use a standard image for Mac OS X, do not bind the image model to Active Directory before making the master image that you will use to image multiple computers. All computers imaged from that master image will use the same computer object in Active Directory, which may cause problems. If you later remove the computer object, all of the Mac OS X computers will be unable to log in with Active Directory user accounts, and you will need to force an unbind, then rebind each computer to Active Directory.

Using System Logs

If the bind fails, check /var/log/system.log, which contains the progress for each step of the binding process listed here:

Step 1 of 6: Searching for Forest/Domain information
Step 2 of 6: Finding nearest Domain controllers
Step 3 of 6: Verifying credentials
Step 4 of 6: Searching for existing computer
Step 5 of 6: Joining new Domain
Step 6 of 6: Writing config

The binding process writes files to /var/db/dslocal/nodes/Default/config/, which only the root user can view.

Confirming DNS Service

The binding process is sensitive to DNS records, so make sure that you specify the Active Directory DNS service in the Network preference of System Preferences, and that port 53 (UDP and TCP, used for DNS requests and replies) to the DNS service is not blocked. If your Active Directory DNS is incorrectly configured, you may experience problems binding Mac OS X to Active Directory.

The Active Directory plug-in requires several DNS service records (SRV) in order to determine which hosts provide certain services on certain protocols. SRV records use the form _Service._Protocol.domain, and the requests are usually in lowercase text. Examples of the searches and replies for a few of the SRV records necessary to bind to Active Directory are shown below:

client17:~ cadmin$ host -t SRV has SRV record 0 100 389
client17:~ cadmin$ host -t SRV has SRV record 0 100 88
client17:~ cadmin$ host -t SRV has SRV record 0 100 464
client17:~ cadmin$ host -t SRV has SRV record 0 100 3268

The host option -t SRV specifies a search of type SRV, and the queries are for various services that are available via the protocol tcp (as opposed to udp) in the domain The key thing to notice is the port number and host offering the service. This example forest is very simple, and the same host offers all the services ( However, the port number is different for each service, as shown here:

  • 389 LDAP
  • 88 Kerberos (used for obtaining Kerberos tickets)
  • 464 Kpasswd (used for making Kerberos password changes)
  • 3268 gc (used for Active Directory Global Catalog lookups)

Although it is possible to use a DNS service that isn’t integrated with Active Directory, many SRV records are required, so it may be difficult to set up all the necessary records and keep them up-to-date.

Confirming Access to Service Ports

After performing SRV requests to find the hosts and ports that offer the required services, you can use telnet to open a connection to a specific port, to verify that you can make a basic connection to each service port. When you see a “Connected to” message from the service, type quit and press Return to end the connection. If you do not see the “Connected to” message, make sure there is no firewall blocking access, check underlying network connectivity, and make sure the service is running on the server.

Below are two examples of using telnet to connect to a port, and the replies from the service. The first connects to port 389 for LDAP service, followed by port 88 for Kerberos service. A failed attempt would stop at “Trying,” but each of these telnet sessions successfully connect to the service:

client17:~ cadmin$ telnet 389
Connected to
Escape character is '^]'.
Connection closed by foreign host.
client17:~ cadmin$ telnet 88
Connected to
Escape character is '^]'.
Connection closed by foreign host.

Understanding the Binding Process

Mac OS X fully supports Active Directory Sites, which allows directory administrators to associate specific domain controllers with specific networks. When you bind a Mac OS X client computer to an Active Directory domain, this kicks off a complicated series of events, shown in the next figure. Understanding the process can help you isolate any problem that might crop up.

Here are the steps, in detail:

  1. Mac OS X performs a request for LDAP, Kerberos, and Kpasswd DNS service records in the domain. If Mac OS X is not using the DNS server that is integrated with Active Directory, the process will likely fail at this point.
  2. Mac OS X binds anonymously with LDAP and gathers basic Active Directory domain information.
  3. DirectoryService’s Active Directory plug-in creates a preliminary Kerberos configuration.
  4. Mac OS X uses the Kerberos configuration, authenticates, and then requests the nearest Domain Controller.
  5. The Domain Controller returns a list of the nearest Domain Controllers, based on the IP subnet of the Mac OS X computer.
  6. Mac OS X confirms that it can connect to the LDAP and Kerberos services of the Domain Controller list from step 5, and DirectoryService and kerberosautoconfig create a final Kerberos configuration in /Library/Preferences/ and /var/db/dslocal/nodes/Default/config/Kerberos:REALM.plist.
  7. Mac OS X connects to what it was told was the nearest Domain Controller.
  8. Mac OS X searches the domain for an existing computer record, and it creates a new computer record to use if it cannot find one.

Specifying a User with Authorization to Bind

When binding, you must provide an Active Directory user name and password. You’ll need to confirm that this user has write privileges for the container in which the computer object will be created or used. If the computer object already exists, the user whom you specify must have write access to the computer object. By default a regular Active Directory user can join and create a computer object only ten times. After that, you will get an error. Here are some workarounds for this limitation:

  • Create the computer object in Active Directory and assign a user or group the ability to join the computer to a domain.
  • Modify the number of times that a particular user can join computers to a domain.
  • Give all authenticated users the unlimited ability to join computers to the domain.
  • Use an administrator account to perform the bind.

Unbinding from Active Directory

You can unbind from Active Directory with either the Directory Utility application or the dsconfigad command with the -r option. If you cannot communicate with the Active Directory service, you can force the unbind. If you force the unbind and the computer object that Mac OS X was using still exists in Active Directory, you can use Active Directory tools to remove the computer object.

In rare circumstances, you may be unable to do a clean unbind from Active Directory. To get a fresh start with the Active Directory plug-in, remove the files that are associated with the Active Directory plug-in, kill DirectoryService, and then try your bind again.

In /Library/Preferences/DirectoryService the files are as follows:

  • ActiveDirectory.plist
  • ActiveDirectoryDomainCache.plist
  • ActiveDirectoryDomainPolicies.plist
  • ActiveDirectoryDynamicData.plist

/Library/Preferences/ will no longer include information about the Active Directory KDC, but do not remove this file if you are bound to any other Kerberos realm.

In /var/db/dslocal/nodes/Default/config/ you can remove these files:

  • Kerberos:REALM.plist, where REALM is your Active Directory Kerberos realm
  • AD DS Plugin.plist

You may also want to remove the following:

  • The computer object in Active Directory that Mac OS X used
  • The record for the Mac OS X computer that the Active Directory plug-in created and updated in the DNS service

If you unbind, change the computer name, and then rebind, you may notice Kerberos errors in /var/log/system.log that reference the old computer name. These occur because the name that you last used to bind to Active Directory may still be found in /Library/Preferences/SystemConfiguration/ in the preferences.plist file, which modifies Do not modify these files, as the errors are harmless and appear only right after you bind.

If the computer object that Mac OS X uses has been deleted or reset, you will not be able to log in using an Active Directory user account. However, if you are troubleshooting, you should be aware that you will be able to obtain a Kerberos TGT for an Active Directory user. However, you will not be able to use su to switch to an Active Directory user, and dirt will return a dDSAuthFailed error even if you supply the correct password. In this case, you must unbind and rebind to Active Directory.

Binding to Active Directory and Open Directory

In any circumstance in which a user account is missing some attributes—for example, because you cannot extend the schema, or you do not have authority to edit the attributes you are interested in—you can always try using the Magic Triangle, in which you use an Open Directory node to supplement data available from the primary node. You learned about this configuration in Chapter 3, in “Augmenting LDAP Data with Information from an Open Directory Server,” and it is illustrated in the figure below.

The Magic Triangle configuration lets you apply Managed Preferences to Open Directory computers and workgroups, and then add Active Directory groups and users to Open Directory workgroups to manage them. See the instructions in Chapter 8, in “Preparing Mac OS X Server for the Magic Triangle Configuration.”

Because the Active Directory plug-in dynamically generates mount records for network home folders, you do not need to provide an additional directory node or mount object to automount an AFP home folder.

  • + Share This
  • 🔖 Save To Your Account

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive:

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020