I'm working on a program that will automate the separation process for users leaving our network. One of the tasks it performs is moving the user account from the OU it is in, to a Former Employees OU. I've been having problems with this step even though I've not had any issues doing other processes with DirectoryServices. Here's my code thus far (note: I know I need to stop catching and eating all exceptions. This will be addressed and corrected before release. Any advice on which exceptions I should catch and which I should not would be appreciated too):
private const string AD_DOMAIN_NAME = "domain.com";
private const string AD_NEW_PASSWORD = "TestPassword123";
private const string AD_FORMER_EMPLOYEES_OU = "LDAP://OU=Former Employees,DC=domain,DC=com";
static DirectoryEntry CreateDirectoryEntry(string connectionPath,
string adUserName, string adPassword)
{
DirectoryEntry ldapConnection = null;
try
{
ldapConnection = new DirectoryEntry(AD_DOMAIN_NAME, adUserName, adPassword);
ldapConnection.Path = connectionPath;
ldapConnection.AuthenticationType = AuthenticationTypes.Secure;
}
catch (Exception ex)
{
MessageBox.Show("Exception Caught in createDirectoryEntry():\n\n" + ex.ToString());
}
return ldapConnection;
}
private void btnProcessSeparation_Click(object sender, EventArgs e)
{
if (cboOffice.SelectedItem != null && lstUsers.SelectedItem != null)
{
string userOU = cboOffice.SelectedItem.ToString();
string userName = lstUsers.SelectedItem.ToString();
string userDn = "LDAP://OU=" + userOU + ",OU=Employees,DC=domain,DC=com";
using (DirectoryEntry ldapConnection = CreateDirectoryEntry(userDn))
{
using (DirectorySearcher searcher = CreateDirectorySearcher(ldapConnection,
SearchScope.OneLevel, "(samaccountname=" + userName + ")", "samaccountname"))
{
SearchResult result = searcher.FindOne();
if (result != null)
{
using (DirectoryEntry userEntry = result.GetDirectoryEntry())
{
if (userEntry != null)
{
using (DirectoryEntry formerEmployees = CreateDirectoryEntry(
AD_FORMER_EMPLOYEES_OU))
{
userEntry.MoveTo(formerEmployees); // This line throws an DirectoryServicesCOMException.
}
userEntry.CommitChanges();
userEntry.Close();
MessageBox.Show("Separation for {0} has completed successfully.", userName);
}
}
}
}
}
}
else
{
MessageBox.Show("Error, you did not select an OU or a user. Please try again.");
}
}
The above code works just fine until the userEntry.MoveTo(formerEmployees); line. That line throws a DirectoryServicesCOMException with the additional information saying An invalid dn syntax has been specified. It is strange because I'm using the same format as the other DirectoryEntry's that work just fine. I've added a break point and confirmed that formerEmployees is set to: LDAP://OU=Former Employees,DC=domain,DC=com. I copied everything after LDAP:// directly from the OU's distinguishedName attribute in Active Directory to make sure it was correct.
Is the space in the OU name causing the problem? I got this to work once just fine and moved on to the other tasks and must have changed something that broke this. I've been looking at the code too much I think and just can't seem to see why it thinks I'm sending an invalid dn.
Thanks for any and all help!
Hope this helps:
DirectoryEntry eLocation = Conexion.Conectar(Localitation);
DirectoryEntry nLocation =Conexion.Conectar(NewLocalitation);
string newName = eLocation.Name;
eLocation.MoveTo(nLocation, newName);
nLocation.Close();
eLocation.Close();
After #David pointed me in the right direction of making sure I had the correct permissions to the OU, I discovered the problem. I added an overloaded CreateDirectoryEntry method that uses the username and password (which is what I put in the code above). However, if you notice in the code above, I call the method that only takes the connection path.
Thanks for the help #David!
I cannot seem to be able to find that a certain user is a member of a DeployUsersProduction group. Here's what I have so far:
[OperationBehavior(Impersonation = ImpersonationOption.Required)]
public Modes GetDeployMode()
{
bool isProd = false;
WindowsIdentity windowsIdentity = WindowsIdentity.GetCurrent();
if (windowsIdentity == null || windowsIdentity.Groups == null) { return Modes.DUS; }
foreach (IdentityReference identityReference in windowsIdentity.Groups)
{
try
{
var reference = identityReference;
string group = reference.Translate(typeof (NTAccount)).Value.Trim();
if (!String.Equals(group, "DeployUsersProduction", StringComparison.OrdinalIgnoreCase)) { continue; }
isProd = true;
break;
}
catch (Exception ex)
{
// Silent catch due to the [Some or all identity references could not be translated]
// error that sometimes occurs while trying to map an identity.
}
}
return isProd ? Modes.Prod : Modes.DUS;
}
I've got all the config, spn, db, perms, etc correct as far as I can tell. I just have one user that should be returning Modes.Prod and it's not.
The answer wasn't that my approach was wrong, it was the fact that I needed to prefix my group that I was searching for with its domain:
if (!String.Equals(group, #"DOMAIN\DeployUsersProd", StringComparison.OrdinalIgnoreCase)) { continue; }
Special thanks to #DJ KRAZE for the links that led me to writing my own Console app that outputted the groups so I could figure this out!
I need to browse ActiveDirectory in order to select computer objects. As I find out, there are some containers that could have computer items, and the other can contain users, group policies, etc. I only want to show the containers which contains computers. So I use this code to check if container contains any computer:
public static bool CheckContainsComputers(DirectoryEntry entry)
{
using (DirectorySearcher ds =
new DirectorySearcher(entry, "(objectCategory=computer)", new string[0], SearchScope.Subtree))
{
ds.Asynchronous = true;
ds.SizeLimit = 1;
try
{
SearchResult sr = ds.FindOne();
return (sr == null) ? false : true;
}
catch
{
return false;
}
}
}
Questions:
In order to reduce the count of call to this method I want to know - is it possible to find out if DirectoryEntry can contain computers without running the DirectorySearcher?
Is it possible with one call to DirectorySearcher with SearchScope.OneLevel to find containers, that can have computers, and computers
1.If you already have your directoryEntry, there is no need to search for it again.
I think what you want is something like this :
if (entry.Properties["objectCategory"].Value.ToString().Contains("Computer"))
return true;
else
return false;
2.
Of course !
DirectoryEntry de = new DirectoryEntry("LDAP://myldapserver.com");
DirectorySearcher directorySearcher = new DirectorySearcher(de);
directorySearcher.SearchScope = SearchScope.OneLevel;
directorySearcher.Filter = "(objectCategory=computer)";
SearchResultCollection srCollection = directorySearcher.FindAll();
Research:
Similar Issue with workaround, but not actual solution to existing problem
Similar issue pointing to Microsoft End Point update as culprit
The above links are the most suited to my problem, I have also viewed every similar question listed by Stack Overflow upon creating this post, and only the above referenced questions fit my issue.
Background:
I have been using UserPrincipal.GetAuthorizationGroups for permissions for specific page access running IIS 7.5 on Server 2008 R2 in a C#.NET 4.0 web forms site for 2 and a half years. On May 15 2013 we removed a primary Domain controller running Server 2008 (not r2) and replaced it with a Server 2012 Domain Controller. The next day we started receiving the exception listed below.
I use Principal Context for Forms Authentication. The username/pass handshake succeeds and the auth cookie is properly set, but the subsequent Principal Context call that also calls UserPrincipal.GetAuthorizationGroups fails intermittently. We've resolved a few BPA issues that appeared in the Server 2012 Domain Controller but this has yet to resolve the issue. I also instituted a cron that runs on two separate servers. The two servers will fail at Group SID resolution at different times though they are running the same code base. (A dev environment and production environment).
The issue resolves itself temporarily upon web server reboot, and also on the dev server it will resolve itself after 12 hours of not functioning. The production server will usually stop functioning properly until a reboot without resolving itself.
At this point I am trying to refine the cron targeting specific Domain Controllers in the network as well as the new DC and using the standard LDAP query that is currently failing to yield more targeted exception times. Thus far we've found on one web server that there is no pattern to the days at which it fails, but it will recover within roughly 12 hours. The latest results show Group SID resolution failure between 8AM-8PM then it recovers, several days later it will fail at 8pm and recover at 8am then run fine for another 12 hours and fail again. We are hoping to see if it is just a specific server communication issue or to see if it is the entire set of Domain Controllers.
Exception:
Exception information:
Exception type: PrincipalOperationException
Exception message: An error (1301) occurred while enumerating the groups.
The group's SID could not be resolved.
at System.DirectoryServices.AccountManagement.SidList.TranslateSids(String target, IntPtr[] pSids)
at System.DirectoryServices.AccountManagement.SidList..ctor(SID_AND_ATTR[] sidAndAttr)
at System.DirectoryServices.AccountManagement.AuthZSet..ctor(Byte[] userSid, NetCred credentials, ContextOptions contextOptions, String flatUserAuthority, StoreCtx userStoreCtx, Object userCtxBase)
at System.DirectoryServices.AccountManagement.ADStoreCtx.GetGroupsMemberOfAZ(Principal p)
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroups()
Question:
Given the above information, does anyone have any idea why decommissioning the Windows Server 2008 (not r2) and implementing a new Server 2012 DC would cause UserPrincipal.GetAuthorizationGroups to fail with the 1301 SID resolution error?
Ideas on eliminating possible causes would also be appreciated.
Disclaimer:
This is my first post to Stack Overflow, I often research here but have not joined in discussions until now. Forgive me if I should have posted elsewhere and feel free to point out better steps before posting.
UPDATE 13-JUN-2013:
On the 12th of June I addressed the possibility of items not disposed causing the issue.
The time frame has been too short to determine if the adjusted code has fixed the issue, but I will continue to update as we work towards a resolution such that maybe with any luck someone here can lend a hand.
Original Code
public bool isGroupMember(string userName, ArrayList groupList)
{
bool valid = false;
PrincipalContext ctx = new PrincipalContext(ContextType.Domain, domain_server + ".domain.org:636", null, ContextOptions.Negotiate | ContextOptions.SecureSocketLayer);
// find the user in the identity store
UserPrincipal user =
UserPrincipal.FindByIdentity(
ctx,
userName);
// get the groups for the user principal and
// store the results in a PrincipalSearchResult object
PrincipalSearchResult<Principal> groups =
user.GetAuthorizationGroups();
// display the names of the groups to which the
// user belongs
foreach (Principal group in groups)
{
foreach (string groupName in groupList)
{
if (group.ToString() == groupName)
{
valid = true;
}
}
}
return valid;
}
Updated Code
public bool isGroupMember(string userName, ArrayList groupList, string domain_server)
{
bool valid = false;
try
{
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain, domain_server + ".domain.org:636", null, ContextOptions.Negotiate | ContextOptions.SecureSocketLayer))
{
// find the user in the identity store
UserPrincipal user =
UserPrincipal.FindByIdentity(
ctx,
userName);
try
{
// get the groups for the user principal and
// store the results in a PrincipalSearchResult object
using (PrincipalSearchResult<Principal> groups = user.GetAuthorizationGroups())
{
// display the names of the groups to which the
// user belongs
foreach (Principal group in groups)
{
foreach (string groupName in groupList)
{
if (group.ToString() == groupName)
{
valid = true;
}
}
group.Dispose();
}
}//end using-2
}
catch
{
log_gen("arbitrary info");
return false;
}
}//end using-1
}
catch
{
log_gen("arbitrary info");
return false;
}
return valid;
}
I have just run into this same issue and the info I have managed to track down may be helpful; as above we have seen this problem where the domain controller is running Server 2012 - firstly with a customer deployment and then replicated on our own network.
After some experimentation we found that our code would run fine on Server 2012, but hit the 1301 error code when the client system was running Server 2008. The key information about what was happening was found here:
MS blog translated from German
The hotfix referred to in the link below has fixed the problem on our test system
SID S-1-18-1 and SID S-1-18-2 can't be mapped
Hope this is helpful for someone! As many have noted this method call seems rather fragile and we will probably look at implementing some alternative approach before we hit other issues.
Gary
Here's my solution. It seems to work consistently well. Because the problem happens when iterating over the collection, I use a different approach when iterating in order to handle the exception without blocking the actual iterating:
private string[] GetUserRoles(string Username)
{
List<string> roles = new List<string>();
try
{
string domain = Username.Contains("\\") ? Username.Substring(0, Username.IndexOf("\\")) : string.Empty;
string username = Username.Contains("\\") ? Username.Substring(Username.LastIndexOf("\\") + 1) : Username;
if (!string.IsNullOrEmpty(domain) && !string.IsNullOrEmpty(username))
{
PrincipalContext principalContext = new PrincipalContext(ContextType.Domain, domain);
UserPrincipal user = UserPrincipal.FindByIdentity(principalContext, username);
if (user != null)
{
PrincipalSearchResult<Principal> groups = user.GetAuthorizationGroups();
int count = groups.Count();
for (int i = 0; i < count; i++)
{
IEnumerable<Principal> principalCollection = groups.Skip(i).Take(1);
Principal principal = null;
try
{
principal = principalCollection.FirstOrDefault();
}
catch (Exception e)
{
//Error handling...
//Known exception - sometimes AD can't query a particular group, requires server hotfix?
//http://support.microsoft.com/kb/2830145
}
if (principal!=null && principal is GroupPrincipal)
{
GroupPrincipal groupPrincipal = (GroupPrincipal)principal;
if (groupPrincipal != null && !string.IsNullOrEmpty(groupPrincipal.Name))
{
roles.Add(groupPrincipal.Name.Trim());
}
}
}
}
}
}
catch (Exception e)
{
//Error handling...
}
return roles.ToArray();
}
We experienced this issue when our infrastructure team brought a 2012 Domain Controller online. We also had pre-2012 DCs in place and so we experienced the issue intermittently. We came up with a fix which I wanted to share - it has 2 parts.
First of all, install the hotfix mentioned by Gary Hill. This will resolve the following issue:
An error (1301) occurred while enumerating the groups. The group's SID could not be resolved.
We thought we were home free after installing this hotfix. However, after it was installed we got a different intermittent error. Certain groups that we were interrogating had a null sAMAccountName property. The actual property was populated in Active Directory but it was incorrectly being returned with a null value by the API. I presume this is a bug somewhere in the Active Directory API but I don't know any more than that.
Fortunately we were able to work around the issue by switching to use the group Name property instead of the sAMAccountName property. This worked for us. I believe, that sAMAccountName is effectively deprecated and exists only for backwards compatibility reasons. That being the case it seemed a reasonable change to make.
I enclose a cut down version of our GetRolesForUser code to demonstrate the change in place.
using (var context = new PrincipalContext(ContextType.Domain, _domainName))
{
try
{
var p = UserPrincipal.FindByIdentity(context, IdentityType.SamAccountName, username);
if (p == null) throw new NullReferenceException(string.Format("UserPrincipal.FindByIdentity returned null for user: {0}, this can indicate a problem with one or more of the AD controllers", username));
var groups = p.GetAuthorizationGroups();
var domain = username.Substring(0, username.IndexOf(#"\", StringComparison.InvariantCultureIgnoreCase)).ToLower();
foreach (GroupPrincipal group in groups)
{
if (!string.IsNullOrEmpty(group.Name))
{
var domainGroup = domain + #"\" + group.Name.ToLower();
if (_groupsToUse.Any(x => x.Equals(domainGroup, StringComparison.InvariantCultureIgnoreCase)))
{
// Go through each application role defined and check if the AD domain group is part of it
foreach (string role in roleKeys)
{
string[] roleMembers = new [] { "role1", "role2" };
foreach (string member in roleMembers)
{
// Check if the domain group is part of the role
if (member.ToLower().Contains(domainGroup))
{
// Cache the Application Role (NOT the AD role)
results.Add(role);
}
}
}
}
}
group.Dispose();
}
}
catch (Exception ex)
{
throw new ProviderException("Unable to query Active Directory.", ex);
}
}
Hope that helps.
I experienced error code 1301 with UserPrincipal.GetAuthorizationGroups while using a brand new virtual development domain which contained 2 workstations and 50 users/groups (many of which are the built in ones). We were running Windows Server 2012 R2 Essentials with two Windows 8.1 Enterprise workstations joined to the domain.
I was able to recursively obtain a list of a user's group membership using the following code:
class ADGroupSearch
{
List<String> groupNames;
public ADGroupSearch()
{
this.groupNames = new List<String>();
}
public List<String> GetGroups()
{
return this.groupNames;
}
public void AddGroupName(String groupName)
{
this.groupNames.Add(groupName);
}
public List<String> GetListOfGroupsRecursively(String samAcctName)
{
PrincipalContext ctx = new PrincipalContext(ContextType.Domain, System.Environment.UserDomainName);
Principal principal = Principal.FindByIdentity(ctx, IdentityType.SamAccountName, samAcctName);
if (principal == null)
{
return GetGroups();
}
else
{
PrincipalSearchResult<Principal> searchResults = principal.GetGroups();
if (searchResults != null)
{
foreach (GroupPrincipal sr in searchResults)
{
if (!this.groupNames.Contains(sr.Name))
{
AddGroupName(sr.Name);
}
Principal p = Principal.FindByIdentity(ctx, IdentityType.SamAccountName, sr.SamAccountName);
try
{
GetMembersForGroup(p);
}
catch (Exception ex)
{
//ignore errors and continue
}
}
}
return GetGroups();
}
}
private void GetMembersForGroup(Principal group)
{
if (group != null && typeof(GroupPrincipal) == group.GetType())
{
GetListOfGroupsRecursively(group.SamAccountName);
}
}
private bool IsGroup(Principal principal)
{
return principal.StructuralObjectClass.ToLower().Equals("group");
}
}
I'm in an environment with multiple domain forests and trusts. I have pretty much this exact same code running on a web site form used to perform user security group lookups across the different domains.
I get this exact error in one of the very large domains where group membership can include 50+ different groups. It works fine in other domains forests.
In my research I found a thread that looks unrelated, but actually has the same stack trace. It is for a remote application running on SBS. The thread mentions that the error is caused by unresolvable SIDS in a group. I believe these would be what are known as "tombstoned" SIDS in active directory. See the thread here.
The thread suggests that finding the tombstoned enteries and removing them from the groups solves the problem. Is it possible the error you are receiving is because SIDS are getting tombstoned every 12 hours by a separate unrelated process? Ultimately, I believe this is a bug in the framework, and that the method should not crash because of tombstoned/unresolvable SIDS.
Good luck!
If anyone is interested this is a VB.NET version of the same code.
Few things you have to do before this code can work
1) You have to reference the assembly System.DirectoryServices
2) Make sure to pass "theusername" variable without the domain, so if your domain is "GIS" and your username is "Hussein" Windows generally authenticate you as GIS\Hussein. So you have to send in just purely the username "Hussein". I worked out the case sensitive stuff.
3) The method GetGroupsNew takes a username and returns a list of groups
4) The method isMemberofnew takes a username and a group and verifies that this user is part of that group or not, this is the one I was interested in.
Private Function getGroupsNew(theusername As String) As List(Of String)
Dim lstGroups As New List(Of String)
Try
Dim allDomains = Forest.GetCurrentForest().Domains.Cast(Of Domain)()
Dim allSearcher = allDomains.[Select](Function(domain)
Dim searcher As New DirectorySearcher(New DirectoryEntry("LDAP://" + domain.Name))
searcher.Filter = [String].Format("(&(&(objectCategory=person)(objectClass=user)(userPrincipalName=*{0}*)))", theusername)
Return searcher
End Function)
Dim directoryEntriesFound = allSearcher.SelectMany(Function(searcher) searcher.FindAll().Cast(Of SearchResult)().[Select](Function(result) result.GetDirectoryEntry()))
Dim memberOf = directoryEntriesFound.[Select](Function(entry)
Using entry
Return New With { _
Key .Name = entry.Name, _
Key .GroupName = DirectCast(entry.Properties("MemberOf").Value, Object()).[Select](Function(obj) obj.ToString()) _
}
End Using
End Function)
For Each user As Object In memberOf
For Each groupName As Object In user.GroupName
lstGroups.Add(groupName)
Next
Next
Return lstGroups
Catch ex As Exception
Throw
End Try
End Function
Private Function isMemberofGroupNew(theusername As String, thegroupname As String) As Boolean
Try
Dim lstGroups As List(Of String) = getGroupsNew(theusername)
For Each sGroup In lstGroups
If sGroup.ToLower.Contains(thegroupname.ToLower) Then Return True
Next
Return False
Catch ex As Exception
Throw
End Try
End Function
we had a similar issue after upgrading the domain controller to 2012. Suddenly my call to user.GetAuthorizationGroups() started failing; I was getting the same exception you were (error 1301). So, I changed it to user.GetGroups(). That worked for a little while, then started failing intermittently on "bad username or password". My latest workaround appears to fix it, for the moment at least. Instead of calling either of those, after constructing the user object, I also construct a group object, one for each group I want to see if the user is a member of. ie, "user.IsMemberOf(group)". That seems to work.
try
{
using (HostingEnvironment.Impersonate())
{
using (var principalContext = new PrincipalContext(ContextType.Domain, "MYDOMAIN"))
{
using (var user = UserPrincipal.FindByIdentity(principalContext, userName))
{
if (user == null)
{
Log.Debug("UserPrincipal.FindByIdentity failed for userName = " + userName + ", thus not authorized!");
isAuthorized = false;
}
if (isAuthorized)
{
firstName = user.GivenName;
lastName = user.Surname;
// so this code started failing:
// var groups = user.GetGroups();
// adGroups.AddRange(from #group in groups where
// #group.Name.ToUpper().Contains("MYSEARCHSTRING") select #group.Name);
// so the following workaround, which calls, instead,
// "user.IsMemberOf(group)",
// appears to work (for now at least). Will monitor for issues.
// test membership in SuperUsers
const string superUsersGroupName = "MyApp-SuperUsers";
using (var superUsers = GroupPrincipal.FindByIdentity(principalContext, superUsersGroupName))
{
if (superUsers != null && user.IsMemberOf(superUsers))
// add to the list of groups this user is a member of
// then do something with it later
adGroups.Add(superUsersGroupName);
}
I had same exception. If someone don't wanna used "LDAP", use this code. Cause I'm had nested groups, I'm used GetMembers(true) and it's little bit longer in time than GetMembers().
https://stackoverflow.com/a/27548271/1857271
or download fix from here: http://support.microsoft.com/kb/2830145
Facing the same problem enumerating authorization groups and the patches noted in the answer did not apply to our web server.
Manually enumerating and ignoring the trouble causing groups is working well, however:
private static bool UserIsMember(string usr, string grp)
{
usr = usr.ToLower();
grp = grp.ToLower();
using (var pc = new PrincipalContext(ContextType.Domain, "DOMAIN_NAME"))
{
using (var user = UserPrincipal.FindByIdentity(pc, usr))
{
var isMember = false;
var authGroups = user?.GetAuthorizationGroups().GetEnumerator();
while (authGroups?.MoveNext() ?? false)
{
try
{
isMember = authGroups.Current.Name.ToLower().Contains(grp);
if (isMember) break;
}
catch
{
// ignored
}
}
authGroups?.Dispose();
return isMember;
}
}
}
I had the problem that if i am connected over VPN and use groups=UserPrincipal.GetGroups() then the Exception occures when iterating over the groups.
If someone want to read all groups of a user there is following possibility (which is faster than using GetGroups())
private IList<string> GetUserGroupsLDAP(string samAccountName)
{
var groupList = new List<string>();
var domainConnection = new DirectoryEntry("LDAP://" + serverName, serverUser, serverUserPassword); // probably you don't need username and password
var samSearcher = new DirectorySearcher();
samSearcher.SearchRoot = domainConnection;
samSearcher.Filter = "(samAccountName=" + samAccountName + ")";
var samResult = samSearcher.FindOne();
if (samResult != null)
{
var theUser = samResult.GetDirectoryEntry();
theUser.RefreshCache(new string[] { "tokenGroups" });
var sidSearcher = new DirectorySearcher();
sidSearcher.SearchRoot = domainConnection;
sidSearcher.PropertiesToLoad.Add("name");
sidSearcher.Filter = CreateFilter(theUser);
foreach (SearchResult result in sidSearcher.FindAll())
{
groupList.Add((string)result.Properties["name"][0]);
}
}
return groupList;
}
private string CreateFilter(DirectoryEntry theUser)
{
string filter = "(|";
foreach (byte[] resultBytes in theUser.Properties["tokenGroups"])
{
var SID = new SecurityIdentifier(resultBytes, 0);
filter += "(objectSid=" + SID.Value + ")";
}
filter += ")";
return filter;
}
For instances when Active Directory takes too long to replicate data between sites, I need to ensure that the local AD replica contains the most up to date information.
How can I get a list of DomainControllers for the current site?
I haven't found anything on Codeproject or on StackOverflow
Going to all this trouble is probably wasted effort. Unless you are experiencing issues with the built in logic for finding a domain controller you should just go with the built in method that returns one. According to Microsoft it automatically tries to find the closes one: http://technet.microsoft.com/en-us/library/cc978016.aspx.
Just use the static DomainController.FindOne method and pass in your directorycontext.
Update
Alright, try the code below, let me know how it works for you. It pings each, returns the roundtrip time, if -1 (no connection) it skips it. Flags PDC status if present. Orders by PDC status, followed by ping round trip.
static void Main(string[] args)
{
var dcsInOrder = (from DomainController c in Domain.GetCurrentDomain().DomainControllers
let responseTime = Pinger(c.Name)
where responseTime >=0
let pdcStatus = c.Roles.Contains(ActiveDirectoryRole.PdcRole)
orderby pdcStatus, responseTime
select new {DC = c, ResponseTime = responseTime}
).ToList();
foreach (var dc in dcsInOrder)
{
System.Console.WriteLine(dc.DC.Name + " - " + dc.ResponseTime);
}
System.Console.ReadLine();
}
private static int Pinger(string address)
{
Ping p = new Ping();
try
{
PingReply reply = p.Send(address, 3000);
if (reply.Status == IPStatus.Success) return (int)reply.RoundtripTime;
}
catch { }
return -1;
}
First, I'll answer the question that you actually asked:
System.DirectoryServices.ActiveDirectory.ActiveDirectorySite.GetComputerSite().Servers
But it seems like you're asking how to make sure that you're talking to the closest domain controller possible. Windows doesn't exactly provide this functionality, the best it will do is give you a domain controller in the same site that the code is running from.
I think the first thing to check is that you have your sites and subnets configured correctly. Run Active Directory Sites and Services, and make sure that subnets and domain controllers are assigned to the correct sites.
This MSDN page (and the Technet article in Peter's answer) says that you must be searching by the DNS name for the DC Locator to attempt to find a DC in the current site. I don't know if the Name property of the Domain class is the DNS domain name.
I have to assume that DomainController.FindOne is a wrapper for DsGetDcName. At that link, you can find how to turn on tracing for that function. You can use this if you still have problems, or maybe you should just PInvoke this function.
Here is a code sample that has no hard coding of DCs. Comments and criticism are welcome.
/// <summary>
/// For best results ensure all hosts are pingable, and turned on.
/// </summary>
/// <returns>An ordered list of DCs with the PDCE first</returns>
static LinkedList<DomainController> GetNearbyDCs()
{
LinkedList<DomainController> preferredDCs = new LinkedList<DomainController>();
List<string> TestedDCs = new List<string>();
using (var mysite = ActiveDirectorySite.GetComputerSite())
{
using (var currentDomain = Domain.GetCurrentDomain())
{
DirectoryContext dctx = new DirectoryContext(DirectoryContextType.Domain, currentDomain.Name);
var listOfDCs = DomainController.FindAll(dctx, mysite.Name);
foreach (DomainController item in listOfDCs)
{
Console.WriteLine(item.Name );
if (IsConnected(item.IPAddress))
{
// Enumerating "Roles" will cause the object to bind to the server
ActiveDirectoryRoleCollection rollColl = item.Roles;
if (rollColl.Count > 0)
{
foreach (ActiveDirectoryRole roleItem in rollColl)
{
if (!TestedDCs.Contains(item.Name))
{
TestedDCs.Add(item.Name);
if (roleItem == ActiveDirectoryRole.PdcRole)
{
preferredDCs.AddFirst(item);
break;
}
else
{
if (preferredDCs.Count > 0)
{
var tmp = preferredDCs.First;
preferredDCs.AddBefore(tmp, item);
}
else
{
preferredDCs.AddFirst(item);
}
break;
}
}
}
}
else
{
// The DC exists but has no roles
TestedDCs.Add(item.Name);
if (preferredDCs.Count > 0)
{
var tmp = preferredDCs.First;
preferredDCs.AddBefore(tmp, item);
}
else
{
preferredDCs.AddFirst(item);
}
}
}
else
{
preferredDCs.AddLast(item);
}
}
}
}
return preferredDCs;
}
static bool IsConnected(string hostToPing)
{
string pingurl = string.Format("{0}", hostToPing);
string host = pingurl;
bool result = false;
Ping p = new Ping();
try
{
PingReply reply = p.Send(host, 3000);
if (reply.Status == IPStatus.Success)
return true;
}
catch { }
return result;
}
Here's my approach using powershell but I'm sure it's a simple implementation in c#, etc. If DHCP is setup correctly, the Primary DNS server in your subnet should be the closest Domain Controller. So the following code should grab the first DNS IP and resolve it to the hostname of the closest DC. This doesn't require RSAT or credentials and contains no specific properties of the current domain.
$NetItems = #(Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "IPEnabled = 'True'" -ComputerName $env:COMPUTERNAME)
foreach ($objItem in $NetItems)
{
if ($objItem.{DNSServerSearchOrder}.Count -ge 1)
{
$PrimaryDNS = $objItem.DNSServerSearchOrder[0]
$domain = $objItem.DNSDomain
break
}
}
[System.Net.Dns]::GetHostbyAddress($PrimaryDNS).hostname -replace ".$($domain)",""