Troubleshooting Connectivity Issues Between Sharepoint And Active Directory

Identifying the Root Cause

When SharePoint is unable to connect to Active Directory domains and infrastructure, the first step is determining the root cause. Check the following areas:

Checking Permissions and Access Control Settings

Validate that the SharePoint servers and services have the necessary permissions to query Active Directory. Review the access control lists on the domain controllers as well as organizational units to ensure the SharePoint computer account and service identities have read permissions.

Validating Network Connectivity

Use networking tools like ping, traceroute, NSlookup to verify TCP/IP connectivity between the SharePoint servers and the Active Directory domain controllers. Check for issues like DNS resolution, latency, packet loss. Ensure firewalls, proxies, routers are not blocking traffic on ports like LDAP 389, Global Catalog 3268, and Kerberos 88.

Verifying DNS Resolution

Confirm that the DNS servers hosting the Active Directory domain zones are reachable from the SharePoint servers. Validate that hostname records for the domain controllers can be successfully resolved. Check for connectivity issues, DNS errors, missing records, or DNS cache pollution.

Reviewing Domain Controller Replication

If SharePoint can connect to some DCs but not others, replication errors might be the culprit. Check the Directory Service event logs for replication failures. Verify naming contexts have replicated successfully across all DCs. Use repadmin and dcdiag tools to test replication topology.

Resolving Authentication Errors

Authentication failures when SharePoint attempts to communicate with Active Directory can manifest in various ways. Some areas to investigate:

Resetting Service Accounts and Passwords

If SharePoint service accounts used for Active Directory access have incorrect or expired passwords, reset the credentials and propagate the new password across SharePoint components. Check for account lockouts as well.

Configuring Delegation Settings

SharePoint requires proper Kerberos protocol transition to fetch user data from Active Directory. Validate that Kerberos delegation is enabled correctly across realms and that SPNs are registered properly.

Enabling Kerberos Authentication

Ensure the SharePoint servers have the EnableKerberos registry value set. Confirm the AES 128/256 encryption types are supported. Set the MaxTokenSize value to 48k+. Check event logs for Preauthentication errors.

Fixing Lookup and Profile Sync Failures

Lookups against Active Directory to fetch user properties and profile sync with user identity repositories rely on connectivity as well. Troubleshoot with:

Confirming User Profile Sync Configuration

Check the User Profile Service Application, User Profile Sync settings for connectivity status. Ensure correct domains are configured properly. Validate import schedule, mappings betweens SharePoint property and Active Directory attribute.

Re-initiating Profile Import and Synchronization

If previous import and sync jobs have failed, re-initiate them. Check status in Monitoring > User Profiles. Compare accounts imported into profile store versus total objects queried form Active Directory.

Clearing Corrupt Data from User Profile Store

If user profiles have invalid or stale data cached locally, clear the cache. Stop the User Profile Service, delete profile db, config db.Restart service and re-sync all profiles.

Recovering from Service Outages

Prolonged periods where SharePoint cannot contact Active Directory can lead to widespread failures. Take these steps to restore services.

Reviewing Services Status and Event Logs

Check health status of key services like User Profile Service Application, Managed Metadata Service. Review Windows Event Log for errors and timeouts. Look for �cannot contact domain controller� messages.

Restarting Related Services

Stop and restart services that consume Active Directory like SharePoint Administration service. Also reset services that cache directory lookups like App Management Service.

Rebuilding Service Application Associations

If service instability has corrupted application pool connectivity parameters, rebuild the association. Start with User Profile SA and manage metadata SA.

Example Code for Connectivity Test

This C# code sample checks if a SharePoint server can successfully connect to Active Directory to run searches:

using System.DirectoryServices;

namespace ADConnectivityCheck 
{
  class Program 
  {
    static void Main(string[] args) 
    {
      try 
      {
        // Specify the AD domain to test
        string domain = "mydomain.com";
              
        // Create directory entry to test domain  
        DirectoryEntry entry = new DirectoryEntry("LDAP://" + domain);

        // Try searching AD for test user account 
        DirectorySearcher searcher = new DirectorySearcher(entry);
        searcher.Filter = "(&(objectClass=user)(samaccountname=testUser))";
        searcher.PropertiesToLoad.Add("cn");
                
        SearchResult result = searcher.FindOne();

        // If query succeeds print success message
        if (result != null) {
          Console.WriteLine("SharePoint can connect to Active Directory domain: " + domain);
        }
      }
      catch (Exception ex)
      {
        // If query fails print error 
        Console.WriteLine("Error connecting to Active Directory: " + ex.Message); 
      }
    }
  }
}