/configuring-pfsense-firewall-rules

name: configuring-pfsense-firewall-rules
description: 'Configures pfSense firewall rules, NAT policies, IPsec/OpenVPN tunnels,
  and traffic shaping to enforce network segmentation and control traffic between
  zones such as DMZ, internal, guest, and IoT. Use when deploying a pfSense perimeter
  or internal firewall, setting up port-forwarding NAT, configuring site-to-site
  or remote-access VPNs, or applying QoS/bandwidth policies.

  '
domain: cybersecurity
subdomain: network-security
tags:
- network-security
- pfsense
- firewall
- nat
- network-segmentation
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- PR.IR-01
- DE.CM-01
- ID.AM-03
- PR.DS-02
mitre_attack:
- T1071.001
- T1095
- T1572
- T1571
- T1041

Configuring 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