Can not access Active Directory domain controller from remote server

Question

I am very new to the LDAP and Active Directory integration portion. Although I successfully configured my local machine to access Active Directory domain controller, when I deployed it on one of our server neither through IP address of the domain nor through domain name it was accessible.

My website is in ASP.NET C#.

It was getting this error:

The specified domain either does not exist or could not be contacted.

My method written to access AD is here:

private SearchResultCollection sResults { get; set; }
sResults = null;

public void SearchByUsername(string username)
{
   try
   {
       // initiate a directory entry
       private const string ldapPath = "LDAP://192.168.0.190/OU=Domain   Users,DC=mydomain,DC=net"                
       dEntry = new DirectoryEntry(ldapPath);

       dSearcher = new DirectorySearcher(dEntry);
       dSearcher.Filter = "(&(objectClass=user)(sAMAccountname= " + username +  "))";

       performSearch();
       getValues();
    }
    catch (Exception)
    {
        throw;
    }
}

private void performSearch()
{
    // perform search in Active Directory
    sResults = dSearcher.FindAll();
}

private void getValues()
{
    // loop through results of search
    foreach (SearchResult sResult in sResults)
    {
        Employee emp = new Employee();

        emp.CN = getProperty(sResult, "cn");
        emp.FirstName = getProperty(sResult, "givenName");
        emp.LastName = getProperty(sResult, "sn");
        emp.Username = getProperty(sResult, "sAMAccountname");
        emp.Email = getProperty(sResult, "mail");

        Employees.Add(emp);
    }
}

Above method works very well on my local machine both with IP address and domain name. Server where I am trying this to work is Windows Server 2012 R2.

I ran command nltest /dclist:mydomain.net and made sure that the server is within the domain as it returned me details. i.e. DC name, IP address, domain name.

Is there any syntactical issue I have run into? OR is it related to configuration issue like DNS ?

Also, like to mention as I tried searching about this on www.serverfault.com but couldn't gather much details.

Please suggest me direction.

are you familiar with PrincipalContext are you aware that you can capture the same information quicker and with less code also on the remote server do you have these assemblies / dll's in the GAC on the Remote Machine using System.DirectoryServices.ActiveDirectory; using System.DirectoryServices.AccountManagement; — MethodMan
@MethodMan: I checked and found these dlls are there on remote machine. but their version is 4.0.**.** and the one which I have in my local machine has 4.6.**.**. Should I replace server ones with my local ones? — Binoy

Binoy Binoy · Accepted Answer · 2015-12-23T21:49:54

Finally things seemed working out.

Earlier I mentioned that I made sure that the machine I am working on is in the domain but things were slightly different there. The machine I am trying to make things work is not actually in the domain but in the workgroup.

Below two Netdom commands helped me identifying this situation.

netdom verify - with this command it is found that machine hasn't joined domain.
netdom join - with this command, was able to join machine to network domain.

Reference: https://technet.microsoft.com/en-us/library/cc772217.aspx

Once it is in domain, Active Directory became immediately accessible.

Can not access Active Directory domain controller from remote server

1 Answers