diff --git a/README.md b/README.md
index 25329d9..4a2b7e6 100644
--- a/README.md
+++ b/README.md
@@ -102,3 +102,4 @@ graph TD
 *   [**Local Development Setup**](./docs/01-dev-env.md)
 *   [**Bare-Metal Hypervisor Preparation**](./docs/02-hypervisor.md)
 *   [**Infrastructure Provisioning with Terraform**](./docs/03-terraform.md)
+*   [**Centralized Identity & DNS Management**](./docs/04-identity.md)
diff --git a/docs/04-identity.md b/docs/04-identity.md
new file mode 100644
index 0000000..e6045ce
--- /dev/null
+++ b/docs/04-identity.md
@@ -0,0 +1,130 @@
+# 🔑 Centralized Identity & DNS Management (FreeIPA)
+
+This document details the configuration, deployment, and operation of the centralized identity domain and directory services managed by **FreeIPA** running on `freeipa.lab.local` (`172.30.1.85`).
+
+---
+
+## 🏛️ Directory & DNS Resolution Architecture
+
+The FreeIPA virtual machine functions as the central authority for authentication, authorization, domain-name resolution, and internal certificates:
+
+```mermaid
+graph LR
+    %% My Color Palette
+    classDef clientNode fill:#212c2a,stroke:#70a99f,color:#f8f8f2,stroke-width:1.5px;
+    classDef ipaNode fill:#2b3b38,stroke:#ff9580,color:#ff9580,stroke-width:1.5px;
+    classDef extNode fill:#212c2a,stroke:#9580ff,color:#f8f8f2,stroke-width:2px;
+
+    subgraph Clients ["Homelab Clients (*.lab.local)"]
+        VMs["🖥️ Guest VMs<br>(portfolio, minecraft, etc.)"]:::clientNode
+    end
+
+    subgraph FreeIPA ["FreeIPA Server (freeipa.lab.local)"]
+        DNS["🌐 BIND DNS Server<br>(Port 53)"]:::ipaNode
+        KDC["🎟️ Kerberos KDC<br>(Ports 88/464)"]:::ipaNode
+        LDAP["🗄️ 389 Directory Server<br>(Ports 389/636)"]:::ipaNode
+        CA["🛡️ Dogtag PKI CA<br>(Certificate Authority)"]:::ipaNode
+    end
+
+    Upstream["🌐 Cloudflare DNS<br>(1.1.1.1)"]:::extNode
+
+    VMs -->|1. Resolves local queries| DNS
+    DNS -->|2. Forwards external queries| Upstream
+    VMs -->|3. Requests Kerberos ticket| KDC
+    VMs -->|4. Authenticates user query| LDAP
+    VMs -->|5. Trusts issued SSL certs| CA
+
+    %% Subgraph Colors
+    style Clients fill:#161d1c,stroke:#70a99f,stroke-width:1px;
+    style FreeIPA fill:#161d1c,stroke:#ff9580,stroke-width:2px;
+```
+
+---
+
+## 📄 Ansible Configuration (`ansible/playbooks/03_freeipa_install.yml`)
+
+The deployment of FreeIPA is automated using Ansible:
+
+### 1.  FQDN and Hostname Setup
+
+Updates the virtual machine kernel hostname to `freeipa.lab.local` to satisfy FreeIPA's strict fully-qualified domain name (FQDN) verification requirements.
+
+### 2.  Package Management
+
+Installs the following packages:
+
+*   `freeipa-server` & `freeipa-server-dns`: The directory server components.
+*   `bind` & `bind-utils`: DNS server utilities.
+*   `firewalld` & `python3-firewall`: Local system firewall management tools.
+
+### 3.  Unattended Server Installation
+
+The playbook runs the installer in non-interactive mode using variables declared in the inventory group variables:
+
+```bash
+ipa-server-install \
+    --unattended \
+    --realm=LAB.LOCAL \
+    --domain=lab.local \
+    --ds-password=xxxxx \
+    --admin-password=xxxxx \
+    --setup-dns \
+    --forwarder=1.1.1.1 \
+    --no-host-dns
+```
+
+*   **Integrated DNS**: DNS is configured to resolve local hosts(`*.lab.local`) and forward unresolved queries to the upstream server (`1.1.1.1`).
+*   **Timeout Handling**: Due to the time-intensive generation of cryptographic PKI keys during installation, the Ansible command timeout is increased to 1200 seconds.
+
+### 4.  Port Protection & Firewall Rules
+
+Ensures the local system firewall allows traffic across the directory network services:
+
+*   `freeipa-ldaps`(Port 636) and `freeipa-ldap`(Port 389)
+*   `dns`(Port 53 TCP/UDP)
+*   `kerberos`(Ports 88/464 TCP/UDP)
+
+---
+
+## 🚀 Execution & Verification
+
+Run the playbook using the following command:
+
+```bash
+ansible-playbook site.yml --tags "freeipa" --ask-vault-pass
+```
+
+### Verification Checks
+
+1.  **Access the GUI Console**: Open a web browser on a workstation connected to the bridge network and navigate to `https://freeipa.lab.local`. Log in using the `admin` username.
+2.  **Kerberos Authentication Check**: SSH into the FreeIPA VM and verify ticket validation:
+
+```bash
+# Request a Kerberos ticket
+kinit admin
+
+# View active ticket credentials
+klist
+```
+
+3.  **DNS Verification**: Query the DNS server directly to verify lookups:
+
+```bash
+dig @172.30.1.85 freeipa.lab.local +short
+# 172.30.1.85
+```
+
+---
+
+## 🔑 Client Enrollment
+
+To enroll a client virtual machine(such as `portfolio` or `minecraft`) into the `LAB.LOCAL` identity realm, execute the client installer on the target node:
+
+```bash
+sudo ipa-client-install \
+    --mkhomedir \
+    --no-ntp \
+    --unattended
+```
+
+*   `--mkhomedir`: Configures PAM(`pam_oddjob_mkhomedir` or `pam_mkhomedir`) to automatically create a local `/home/` directory upon a user's first login via SSH.