User Authentication in Active Directory - Windows Server 2012 R2

Question

We have a situation with Active Directory during project startup:

Environment Information: Central server that has the Main Active Directory server : Windows server 2012 R2 64-bit, IP Address: 192.168.1.10

Office server that has a read only Active Directory server: Windows server 2012 R2 64-bit, IP Address: 192.168.50.10 (this Active directory replicates users & workstations information from the central server). The two server are connected via a DSL network.

Our C# application runs on the office network and the Operator PC (Windows 7 64-bit) is joined to the domain in the office. it has to authenticate users from Active Directory in the Office Server using the following code.

 using (PrincipalContext pc = new PrincipalContext(ContextType.Domain, "mydomain.com"))
                    {
                        // validate the credentials
                        bool isValid = pc.ValidateCredentials("username", "password");
                        Log("Create principal context done");
                    }

The problem is we have the following errors that appear almost every time we try to run this code:

1. The server is not operational
2. The server could not be contacted
3. The LDAP server is unavailable

In case this code works it take about 1 minutes to finish. Note: this code never fail in our development environment (LAN network with the same IP range 10.0.0. ).

Any suggestions?

Answer 1

Do you have any firewall or DNS issues?

Are you sure you are calling the correct server?