Setting up 3DCs in the Same VLAN Network: Domain Controller Access Issues with Full Control on DC3
In this article, we will discuss the process of setting up three Domain Controllers (DCs) in the same VLAN network, with a particular focus on access issues that can arise when granting full control to a company's data on DC3.
Background
A VLAN (Virtual Local Area Network) is a network that allows for the creation of separate logical sub-networks within a single physical network. By creating multiple VLANs, an organization can segment its network and improve security by limiting the scope of broadcast domains and restricting communication between different VLANs.
In this setup, we have three Domain Controllers (DC1, DC2, and DC3) that are all connected to the same VLAN. This allows for seamless communication between the DCs and provides redundancy and fault tolerance for the domain.
Problem
The problem arises when a company wants to grant full control of its data to DC3. This can cause access issues, as DC3 may not be able to properly communicate with the other DCs in the network due to security restrictions put in place by the VLAN.
Solution
To solve this issue, we need to properly configure the VLAN and the DCs to allow for full communication between them. This can be done by following these steps:
- Verify that all DCs are on the same VLAN
- Configure the firewall rules to allow communication between the DCs
- Verify that the necessary ports are open for communication between the DCs
- Grant the necessary permissions to DC3 to allow for full control of the data
Configuring the VLAN
The first step is to ensure that all DCs are on the same VLAN. This can be done by checking the VLAN configuration on the switch that the DCs are connected to. If the DCs are not on the same VLAN, they will need to be moved to the same VLAN in order to communicate with each other.
Configuring the Firewall
Once the DCs are on the same VLAN, the next step is to configure the firewall rules to allow communication between them. This can be done by creating rules that allow traffic to flow between the DCs on the necessary ports.
Verifying Necessary Ports
In order for the DCs to communicate with each other, certain ports need to be open. These ports include:
- TCP 88: Kerberos authentication
- TCP 135: RPC endpoint mapper
- TCP 139: NetBIOS session service
- TCP 389: LDAP
- TCP 636: LDAP over SSL
- TCP 3268: Global catalog
- TCP 3269: Global catalog over SSL
Granting Permissions
Once the VLAN and firewall have been properly configured, the final step is to grant the necessary permissions to DC3 to allow for full control of the data. This can be done by adding the appropriate permissions to the DC3 computer account in Active Directory.
Setting up multiple Domain Controllers in the same VLAN network can provide many benefits, including redundancy and fault tolerance. However, it is important to properly configure the VLAN and the DCs to allow for full communication between them. By following the steps outlined in this article, you can ensure that your DCs are properly configured and that you are able to grant full control of your data to the appropriate DC without encountering access issues.
References
- Planning for Security Considerations for Domain Controllers
- Best Practices for Securing Active Directory
- Securing Active Directory Services with Group Policy
// Example of properly formatted code block
function grantFullControl(dc) {
// Code to grant full control to the specified DC
}