Module 13: Designing Networking Services in Microsoft Windows Server

To provide knowledge and best practices for designing and deploying integrated networking services using Microsoft Windows Server. This includes planning, implementing, and securing services like DNS, DHCP, IPAM, VPN, DirectAccess, and RADIUS.

Key Topics Covered

1. Planning a Network Services Infrastructure

Identifying business and technical requirements
Designing address schemes (IPv4/IPv6)
Mapping services to organizational structure
Planning high availability and redundancy

2. Designing DHCP Services

Scope planning and lease management
Failover configuration (load balance vs hot standby)
DHCP policies and reservations
DHCP with IPAM integration

3. Designing DNS Services

Internal vs External DNS design
Forwarders, Root Hints, Stub Zones
DNSSEC for secure name resolution
Zone replication and delegation

4. Integrating IPAM (IP Address Management)

Centralized IP address tracking and planning
Integration with DHCP and DNS
Role-based access and auditing

5. Designing Remote Access Services

VPN design (IKEv2, SSTP, L2TP)
DirectAccess for seamless internal access
NAT and routing roles
Security and scalability considerations

6. Designing RADIUS and NPS

Authentication and Authorization for remote users
Network Policy Server (NPS) deployment
Integrating with AD and certificate services
Redundancy and performance tuning

Security and Compliance Considerations

Implementing least privilege on service roles
Encrypting data in transit (TLS, IPsec)
Multi-factor authentication for remote access
Monitoring and logging network services

Design Tools and Techniques

Windows Admin Center
PowerShell for service deployment
Group Policy for service management
Performance Monitor and Event Viewer for troubleshooting

Outcomes

By the end of this module, you should be able to:

Design a secure, scalable, and resilient network services infrastructure
Combine and optimize DNS, DHCP, IPAM, VPN, and RADIUS services
Apply high availability and fault tolerance best practices
Monitor, audit, and troubleshoot deployed services effectively

Evaluating the Existing Configuration

Evaluating the existing configuration is a critical step before designing or modifying network services. This process helps identify current capabilities, limitations, and potential improvement areas.

1. Assessing Current Network Infrastructure

Topology Review: Examine physical and logical network diagrams.
IP Scheme Analysis: Review IPv4/IPv6 addressing structure for conflicts or inefficiencies.
Device Inventory: List routers, switches, servers, and client systems.
Network Segmentation: Check for VLANs, subnets, and DMZ configurations.

2. Reviewing Deployed Services

DHCP:
- Are scopes properly configured?
- Any overlapping address ranges?
- Is failover enabled?
DNS:
- Are zones active and replicating properly?
- Are forwarders, stub zones, or conditional forwarders in use?
- Is DNSSEC implemented?
IPAM:
- Is IPAM deployed and properly syncing with DHCP/DNS?
- Are IP utilization and address tracking enabled?
RADIUS/NPS:
- Are policies aligned with security requirements?
- Are authentication logs being stored?
- Is redundancy configured?
Remote Access (VPN/DirectAccess):
- What protocols are in use (IKEv2, SSTP, etc.)?
- Are there performance or connection issues?
- Is split tunneling enabled or disabled?

3. Evaluating Security Settings

Firewall Rules: Review inbound/outbound rules for key services.
Certificates: Check expiry and validity for services using SSL/TLS.
User Access Control: Assess role-based permissions and group memberships.
Audit Logs: Ensure proper logging and review practices are in place.

4. Performance and Availability Metrics

Uptime/Downtime Reports
DHCP Lease Utilization
DNS Query Load
Network Latency and Throughput
Failover and Redundancy Testing

5. Configuration Documentation

Ensure all current configurations are well-documented.
Review Group Policy Objects (GPOs) affecting networking services.
Check for PowerShell scripts or automation routines in use.

Next Steps After Evaluation

Identify misconfigurations or outdated practices.
Document areas needing improvement or redesign.
Prioritize changes based on risk, performance, and security.

Identifying the Essential Design Decisions

When designing or redesigning networking services in Windows Server, it is critical to identify the essential design decisions that directly affect the performance, scalability, availability, and security of the infrastructure.

1. Network Architecture Design

Topology: Choose between flat, hierarchical, or hybrid network designs.
Segmentation: Decide on VLAN/subnet structure for security and traffic management.
IP Addressing Strategy: Use static, dynamic, or hybrid addressing schemes.
Naming Conventions: Standardize DNS domain names and NetBIOS names.

2. Core Infrastructure Services

DHCP Design:
- Scope sizing and distribution.
- High availability (failover vs. split scope).
- Lease duration and reservations.
DNS Design:
- Zone types (primary, secondary, stub, AD-integrated).
- Forwarders and root hints usage.
- Internal vs. external name resolution separation.
Active Directory Sites and Services:
- Site design based on physical locations.
- Replication scheduling and bridgehead server configuration.

3. Authentication and Access Control

RADIUS/NPS:
- Policy structure (connection request, network, health).
- Integration with Active Directory or external authentication sources.
- Load balancing and redundancy planning.
VPN and Remote Access:
- Protocol selection (SSTP, L2TP/IPsec, IKEv2).
- Conditional access or MFA integration.
- Design for split tunneling or full-tunnel VPN.

4. Scalability and High Availability

Failover Clustering:
- Where applicable (DHCP, File Server, etc.).
Redundancy:
- Redundant DNS servers, DHCP failover pairs.
Load Balancing:
- For services like RADIUS, Web Services, etc.

5. Security Decisions

Firewall Design:
- Granular control via Windows Firewall with Advanced Security.
Certificates and PKI:
- Internal CA deployment for service and user authentication.
Logging and Auditing:
- Use of centralized log collection and alerts.

6. Integration with Other Services

Azure AD / Hybrid Identity:
- Sync requirements, domain join choices.
IPAM Integration:
- Use for centralized management of IP space.
Group Policy Design:
- Delegation, inheritance, and filtering structure.

7. Management and Monitoring

Monitoring Tools:
- Use of Performance Monitor, Event Viewer, or third-party tools.
Alerting Mechanisms:
- SCOM or custom scripts/solutions.
Automation:
- PowerShell scripts for service provisioning and validation.

Providing Security in Networking Service Designs (Windows Server)

Designing secure networking services in Windows Server involves layered security principles to protect systems, data, and communications from unauthorized access, abuse, or disruption.

1. Secure Authentication and Authorization

Active Directory (AD) Security:
- Use organizational units (OUs) and Group Policy Objects (GPOs) for policy enforcement.
- Implement Least Privilege Access and use Role-Based Access Control (RBAC).
Multi-Factor Authentication (MFA):
- Integrate with NPS, RADIUS, or Azure AD.
Password Policies:
- Enforce complexity, expiration, and lockout rules.

2. Network Access Protection

Network Policy Server (NPS):
- Centralize RADIUS policies and health validation.
VPN Security:
- Use IKEv2, SSTP, or L2TP/IPsec with strong encryption.
- Enforce split-tunnel or full-tunnel based on risk assessment.

3. Firewall and Traffic Control

Windows Defender Firewall with Advanced Security:
- Configure inbound/outbound rules for services.
- Apply GPO-based firewall settings for consistency.
Network Segmentation:
- Use VLANs and subnets to isolate sensitive systems.
- Implement Access Control Lists (ACLs) on routers/switches.

4. Secure DNS and DHCP

DNS Security:
- Use DNSSEC to protect against spoofing.
- Restrict zone transfers and enable auditing.
DHCP Security:
- Use DHCP Snooping on switches (hardware-level).
- Secure DHCP server with scope-level permissions.

5. Public Key Infrastructure (PKI)

Deploy Active Directory Certificate Services (AD CS):
- Use for authentication (VPN, RADIUS, web apps).
- Issue certificates to users, computers, and services.
Certificate Revocation List (CRL) and OCSP:
- Keep revocation mechanisms up to date and published.

6. Auditing and Logging

Event Viewer:
- Enable auditing of logons, policy changes, access attempts.
Syslog/SIEM Integration:
- Forward logs to centralized systems for correlation and alerting.

7. Patch and Update Management

Windows Server Update Services (WSUS) or Intune:
- Regularly patch OS and networking services.
Enable automatic updates with approval policies.

8. Secure Remote Administration

Use RDP over VPN only, or enforce Just-in-Time (JIT) access.
Restrict admin tools to jump servers.
PowerShell Remoting should use HTTPS and require mutual authentication.

9. Disable Unused Services

Minimize attack surface by disabling:
- Telnet, FTP, SMBv1, and other legacy protocols.
- Unused roles and features in Server Manager.

10. Backup and Recovery Security

Encrypt backup files.
Use BitLocker on backup drives.
Restrict backup restore access to trusted personnel.

Enhancing Availability and Performance of Networking Services

Improving availability and performance in Windows Server networking environments ensures business continuity, responsiveness, and scalability. Below is a structured guide to enhancing both.

1. High Availability (HA) Strategies

a. Redundancy

NIC Teaming: Combine multiple network adapters for fault tolerance.
DNS/DHCP Failover:
- Configure DHCP failover mode (Load balance or Hot standby).
- Use primary and secondary DNS servers.
Clustered Services:
- Use Failover Clustering for DHCP, DNS, and File Servers.

b. Load Balancing

Network Load Balancing (NLB):
- Distribute traffic across multiple servers (e.g., RDS, web apps).
DNS Round Robin:
- Balance load using DNS for non-critical services.

c. Fault Tolerance

Implement RAID on storage.
Use UPS and redundant power supplies.

2. Performance Optimization Strategies

a. Network Optimization

QoS (Quality of Service):
- Prioritize critical traffic (e.g., VoIP, RDP).
- Configure via Group Policy.
TCP/IP Optimization:
- Tune TCP window size, offload settings on NICs.

b. DNS and DHCP Performance

Use scavenging to clean stale DNS records.
Place DHCP servers closer to clients or use relay agents.

c. Server Performance Tuning

Allocate enough RAM/CPU based on role (DNS, DHCP, NPS).
Use performance monitor counters to track bottlenecks.

3. Scalability & Resource Management

Implement Windows Admin Center for centralized performance monitoring.
Use Dynamic Host Configuration Protocol (DHCP) scope splitting to manage growing client bases.
Use Virtualization (Hyper-V) to scale services dynamically.

4. Security Measures That Support Uptime

Regular patching with WSUS or Intune to reduce downtime from vulnerabilities.
Monitor with System Center Operations Manager (SCOM) or third-party tools.
Backup and restore tests to recover quickly after a failure.