Configuring pfSense Firewall Rules
FreeStreamline your pfSense firewall configuration process.
Free · Opens the source repo
What Configuring pfSense Firewall Rules does
The Configuring pfSense Firewall Rules skill provides a structured approach to setting up firewall rules, NAT policies, and VPN configurations on pfSense, a popular open-source firewall and router software. This skill is designed for network administrators and IT professionals who need to enforce network segmentation and manage traffic flow between different zones such as DMZ, internal networks, guest networks, and IoT devices. By following the detailed steps provided in the skill, users can ensure that their network infrastructure is secure and well-organized.
This skill guides users through the essential configurations required when deploying pfSense, including defining network interfaces and VLANs, setting up DHCP and DNS for each zone, and creating firewall rule aliases. The workflow is clearly outlined, allowing users to implement granular access control rules that restrict traffic between VLANs and network segments. Additionally, the skill covers NAT configurations for port forwarding, ensuring that internal services can be accessed securely from the internet.
Whether you are setting up a new pfSense installation or optimizing an existing one, this skill is invaluable for maintaining a secure network environment. It is particularly useful for those deploying a perimeter firewall or internal firewall, as well as for configuring site-to-site or remote-access VPNs using IPsec or OpenVPN. The emphasis on traffic shaping and bandwidth management also helps in meeting quality-of-service requirements, making this skill a comprehensive tool for network management.
When to use it
Use this skill when deploying or managing a pfSense firewall to ensure proper segmentation and security across network zones.
When not to use it
This skill is not suitable for configuring host-based firewalls or for scenarios requiring deep packet inspection without dedicated hardware.
What you can build with it
Setting Up a New pfSense Firewall
When deploying a new pfSense firewall, this skill guides you through the entire configuration process for interfaces, VLANs, and firewall rules.
Optimizing Existing Firewall Rules
Use this skill to review and enhance your current pfSense firewall rules and NAT policies for better security and performance.
Configuring VPN Access for Remote Users
This skill helps you set up secure remote access VPNs, ensuring that remote users can connect safely to your network.
How to install Configuring pfSense Firewall Rules
View source1. Install with the skills CLI
npx skills add mukul975/anthropic-cybersecurity-skills/configuring-pfsense-firewall-rules --agent claude-code2. Or install it manually
Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.
Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs
Inside SKILL.md
Written by mukul975Configuring pfSense Firewall Rules
When to Use
- Deploying a perimeter or internal firewall to segment and protect network zones (DMZ, internal, guest, IoT)
- Creating granular access control rules to restrict traffic between VLANs and network segments
- Configuring NAT rules for port forwarding to internal services exposed to the internet
- Setting up site-to-site or remote access VPN tunnels using IPsec or OpenVPN
- Implementing traffic shaping and bandwidth management for quality-of-service requirements
Do not use as a substitute for host-based firewalls on individual systems, for SSL/TLS deep packet inspection without dedicated hardware acceleration, or as the sole security control without complementary IDS/IPS.
Prerequisites
- pfSense 2.7+ installed on dedicated hardware or virtual machine with at least two network interfaces
- Access to the pfSense WebConfigurator (default: https://192.168.1.1)
- Network topology diagram showing all interfaces, VLANs, and desired traffic flow
- DNS and DHCP configuration planned for each network zone
- Understanding of TCP/IP, NAT, and stateful firewall concepts
Workflow
Step 1: Configure Network Interfaces and VLANs
Access the pfSense WebConfigurator and define interfaces:
Navigate: Interfaces > Assignments
WAN Interface (igb0):
- Type: DHCP or Static IP from ISP
- Block private networks: Enabled
- Block bogon networks: Enabled
LAN Interface (igb1):
- IPv4: 10.10.1.1/24
- Description: CORPORATE_LAN
Create VLANs:
Navigate: Interfaces > VLANs > Add
- VLAN 10 on igb1: DMZ (10.10.10.1/24)
- VLAN 20 on igb1: SERVERS (10.10.20.1/24)
- VLAN 30 on igb1: GUEST (10.10.30.1/24)
- VLAN 40 on igb1: IOT (10.10.40.1/24)
Assign VLANs:
Navigate: Interfaces > Assignments > Add each VLAN
Enable each interface and assign the gateway IP
Step 2: Configure DHCP and DNS for Each Zone
Navigate: Services > DHCP Server
CORPORATE_LAN (10.10.1.0/24):
Range: 10.10.1.100 - 10.10.1.200
DNS: 10.10.20.10 (internal DNS server)
Gateway: 10.10.1.1
DMZ (10.10.10.0/24):
Range: 10.10.10.100 - 10.10.10.200
DNS: 10.10.20.10
Gateway: 10.10.10.1
GUEST (10.10.30.0/24):
Range: 10.10.30.100 - 10.10.30.200
DNS: 1.1.1.1, 8.8.8.8 (public DNS only)
Gateway: 10.10.30.1
Navigate: Services > DNS Resolver
Enable DNS Resolver on all interfaces except GUEST
Enable DNSSEC
Configure forwarding to upstream DNS servers
Step 3: Create Firewall Rule Aliases
Navigate: Firewall > Aliases
RFC1918_Networks:
Type: Network
Values: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
WebPorts:
Type: Port
Values: 80, 443
ManagementPorts:
Type: Port
Values: 22, 3389, 5900
CriticalServers:
Type: Host
Values: 10.10.20.10, 10.10.20.11, 10.10.20.12
BlockedCountries:
Type: URL Table
URL: https://www.ipdeny.com/ipblocks/data/aggregated/cn-aggregated.zone
Update: 24 hours
Step 4: Implement Firewall Rules by Zone
Navigate: Firewall > Rules
=== WAN Rules ===
# Block all inbound by default (implicit deny)
# Allow established/related traffic (automatic in pfSense stateful mode)
# Allow inbound to DMZ web server (via NAT)
Action: Pass | Interface: WAN | Protocol: TCP
Source: any | Destination: WAN Address | Port: 80, 443
Description: Allow HTTP/HTTPS to DMZ web server
=== LAN Rules ===
# Allow LAN to access internal servers
Action: Pass | Interface: LAN | Protocol: TCP
Source: LAN net | Destination: SERVERS net | Port: WebPorts, 3306, 5432
Description: Allow LAN to internal web and database servers
# Allow LAN to internet
Action: Pass | Interface: LAN | Protocol: any
Source: LAN net | Destination: ! RFC1918_Networks
Description: Allow LAN to internet (block inter-VLAN via RFC1918 exclusion)
# Block LAN to IoT (explicit deny before implicit allow)
Action: Block | Interface: LAN | Protocol: any
Source: LAN net | Destination: IOT net
Description: Block direct LAN to IoT communication
=== DMZ Rules ===
# Allow DMZ web servers to query internal DNS
Action: Pass | Interface: DMZ | Protocol: TCP/UDP
Source: DMZ net | Destination: 10.10.20.10 | Port: 53
Description: Allow DMZ DNS queries to internal resolver
# Allow DMZ to internet for updates only
Action: Pass | Interface: DMZ | Protocol: TCP
Source: DMZ net | Destination: any | Port: 80, 443
Description: Allow DMZ outbound HTTP/HTTPS for updates
# Block all other DMZ traffic
Action: Block | Interface: DMZ | Protocol: any
Source: DMZ net | Destination: any
Description: Default deny for DMZ
=== GUEST Rules ===
# Allow guest to internet only (DNS and web)
Action: Pass | Interface: GUEST | Protocol: TCP/UDP
Source: GUEST net | Destination: ! RFC1918_Networks | Port: 53, 80, 443
Description: Allow guest internet access only
# Block all guest to internal
Action: Block | Interface: GUEST | Protocol: any
Source: GUEST net | Destination: RFC1918_Networks
Description: Block guest access to all internal networks
=== IOT Rules ===
# Allow IoT to specific cloud endpoints
Action: Pass | Interface: IOT | Protocol: TCP
Source: IOT net | Destination: ! RFC1918_Networks | Port: 443, 8883
Description: Allow IoT HTTPS and MQTT to cloud
# Block IoT inter-device communication
Action: Block | Interface: IOT | Protocol: any
Source: IOT net | Destination: IOT net
Description: Prevent IoT lateral movement
# Block IoT to all internal networks
Action: Block | Interface: IOT | Protocol: any
Source: IOT net | Destination: RFC1918_Networks
Description: Block IoT access to internal
Step 5: Configure NAT Rules
Navigate: Firewall > NAT > Port Forward
# Web server in DMZ
Interface: WAN | Protocol: TCP
Destination: WAN address | Port: 443
Redirect target IP: 10.10.10.50 | Port: 443
NAT Reflection: Enable
Description: HTTPS to DMZ web server
# SSH jump host (non-standard port)
Interface: WAN | Protocol: TCP
Destination: WAN address | Port: 2222
Redirect target IP: 10.10.20.11 | Port: 22
Description: SSH to internal jump host via port 2222
Navigate: Firewall > NAT > Outbound
Mode: Hybrid Outbound NAT
# Add rule for DMZ servers to use a dedicated public IP
Interface: WAN | Source: 10.10.10.0/24
Translation Address: <dedicated_public_ip>
Description: DMZ outbound NAT via dedicated IP
Step 6: Enable Logging and Monitoring
Navigate: Status > System Logs > Settings
Remote Logging: Enable
Remote log servers: 10.10.20.15:514 (Syslog/SIEM)
Log firewall default blocks: Enabled
Navigate: Firewall > Rules
Enable logging on critical rules:
- All BLOCK rules
- WAN inbound PASS rules
- Inter-VLAN PASS rules
Navigate: Diagnostics > pfTop
Monitor real-time connection states and bandwidth usage
Install pfBlockerNG package:
Navigate: System > Package Manager > Available Packages
Install pfBlockerNG-devel
Configure IP blocklists (Spamhaus DROP, Emerging Threats)
Configure DNSBL for malware domain blocking
Step 7: Backup and Test Configuration
# Export configuration backup
Navigate: Diagnostics > Backup & Restore
Download XML configuration file
# Test rules from each zone
# From LAN:
curl -I https://10.10.20.10 # Should succeed (LAN to SERVERS)
curl -I https://10.10.40.5 # Should fail (LAN to IOT blocked)
# From GUEST:
curl -I https://www.google.com # Should succeed (internet)
curl -I https://10.10.20.10 # Should fail (guest to internal blocked)
# From DMZ:
nslookup google.com 10.10.20.10 # Should succeed (DNS allowed)
ssh 10.10.1.50 # Should fail (DMZ to LAN blocked)
# Verify logging
Navigate: Status > System Logs > Firewall
Check that blocked and passed traffic is logging correctly
# Schedule automated config backups
Navigate: Diagnostics > AutoConfigBackup
Enable automatic backups to Netgate cloud or local storage
Key Concepts
| Term | Definition |
|---|---|
| Stateful Firewall | Firewall that tracks the state of network connections and automatically allows return traffic for established sessions without explicit rules |
| Alias | Named group of IP addresses, networks, or ports in pfSense that simplifies rule management and improves readability |
| NAT (Network Address Translation) | Translation of IP addresses between internal and external networks, including port forwarding for inbound access to internal services |
| Floating Rules | pfSense rules that apply across multiple interfaces simultaneously, processed before per-interface rules |
| pfBlockerNG | pfSense package that integrates IP reputation blocklists and DNS-based blocklists for automated threat blocking |
| Rule Processing Order | pfSense evaluates rules top-to-bottom within each interface tab; first match wins, and unmatched traffic is blocked by default |
Tools & Systems
- pfSense 2.7+: Open-source firewall and router platform based on FreeBSD with web-based management and extensive package ecosystem
- pfBlockerNG: IP and DNS blocklist package for automated threat intelligence integration
- Snort/Suricata packages: IDS/IPS integration available as pfSense packages for inline traffic inspection
- OpenVPN/IPsec: Built-in VPN implementations for site-to-site and remote access connectivity
- Netgate AutoConfigBackup: Cloud-based configuration backup service for pfSense disaster recovery
Common Scenarios
Scenario: Segmenting a Small Business Network with pfSense
Context: A medical practice needs to segment its network to meet HIPAA requirements. They have a single internet connection, an electronic health records (EHR) server, staff workstations, a guest WiFi network, and medical IoT devices (vitals monitors, imaging equipment). Budget constraints require an open-source solution.
Approach:
- Deploy pfSense on a Netgate 4100 appliance with four physical interfaces (WAN, LAN, DMZ, MGMT)
- Create VLANs for staff (VLAN 10), EHR servers (VLAN 20), guest WiFi (VLAN 30), and medical devices (VLAN 40)
- Configure strict rules: staff VLAN can access EHR servers on HTTPS only; medical devices can communicate only with the EHR server on specific ports; guest WiFi gets internet-only access with no internal routing
- Enable pfBlockerNG with healthcare-specific threat feeds and malware domain blocking
- Configure outbound NAT to prevent internal IP addresses from leaking to the internet
- Enable comprehensive logging and forward all firewall logs to a SIEM via syslog
- Set up automated configuration backups and document the rule base for audit compliance
Pitfalls:
- Creating rules that are too permissive ("allow any any") instead of specific port-based rules
- Forgetting the rule processing order -- placing a broad PASS rule above a specific BLOCK rule
- Not enabling logging on critical rules, making incident investigation impossible
- Allowing IoT devices unrestricted internet access, creating potential data exfiltration paths
Output Format
## pfSense Firewall Configuration Report
**Device**: pfSense 2.7.2 on Netgate 4100
**Interfaces**: WAN (igb0), LAN (igb1), DMZ (igb2), MGMT (igb3)
**VLANs**: 4 configured (Staff, Servers, Guest, IoT)
**Total Rules**: 28 active rules across all interfaces
### Rule Summary by Interface
| Interface | Pass Rules | Block Rules | Logging Enabled |
|-----------|-----------|-------------|-----------------|
| WAN | 2 | 1 (default) | Yes |
| LAN | 4 | 2 | Yes (blocks) |
| DMZ | 3 | 1 (default) | Yes |
| GUEST | 1 | 2 | Yes |
| IOT | 1 | 3 | Yes |
### Security Controls
- pfBlockerNG: 12 IP blocklists + DNSBL enabled
- Snort IDS: Running on WAN and LAN interfaces
- VPN: OpenVPN remote access configured with MFA
- Logging: All traffic forwarded to SIEM (10.10.20.15)
Frequently asked questions about Configuring pfSense Firewall Rules
Similar skills
Resemble Detect
Detect and analyze AI-generated media for authenticity.
Licenca para Auditar
Comprehensive security audits and threat modeling for projects.
Authenticated Vulnerability Scan
Run deep vulnerability scans with valid credentials.
Agentless Vulnerability Scanning
Assess systems for vulnerabilities without agents.
Implementing Rapid7 InsightVM for Scanning
Streamline vulnerability management with InsightVM setup.
Next-Generation Firewall Deployment
Streamline Palo Alto firewall configuration and management.