Configuring Pfsense Firewall Rules

---
name: configuring-pfsense-firewall-rules
description: Configures pfSense firewall rules, NAT policies, VPN tunnels, and traffic shaping to enforce network segmentation, control traffic flow, and protect internal network zones in enterprise and
  small-to-medium business environments.
tags:
- pfsense
- network-segmentation
- nat
- network-security
- fetih
- cybersecurity
- firewall
- siber-güvenlik
triggers:
- IDS
- IPS
- api
- ağ güvenliği
- cloud
- configuring
- dns
- endpoint
- firewall
- http
- incident
- log
category: network-security
source_subdomain: network-security
nist_csf:
- PR.IR-01
- DE.CM-01
- ID.AM-03
- PR.DS-02
adapted_for: fetih
---

# Configuring Pfsense Firewall Rules


## Ne Zaman Kullanılır

- Dağıt:ing 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

**Kullanma:** as a substitute for host-based firewalls on individual systems, for SSL/TLS deep packet Denetle:ion without dedicated hardware acceleration, or as the sole security control without complementary IDS/IPS.

## Ön Gereksinimler

- pfSense 2.7+ kurulu: dedicated hardware or virtual machine with at least two network interfaces
- Erişim: 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

## İş Akışı

### Adım 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
```

### Adım 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
```

### Adım 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
```

### Adım 4: Implement Firewall Rules by Zone

```
Navigate: Firewall > Rules

=== WAN Rules ===

Action: Pass | Interface: WAN | Protocol: TCP
Source: any | Destination: WAN Address | Port: 80, 443
Description: Allow HTTP/HTTPS to DMZ web server

=== LAN Rules ===
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

Action: Pass | Interface: LAN | Protocol: any
Source: LAN net | Destination: ! RFC1918_Networks
Description: Allow LAN to internet (block inter-VLAN via RFC1918 exclusion)

Action: Block | Interface: LAN | Protocol: any
Source: LAN net | Destination: IOT net
Description: Block direct LAN to IoT communication

=== DMZ Rules ===
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

Action: Pass | Interface: DMZ | Protocol: TCP
Source: DMZ net | Destination: any | Port: 80, 443
Description: Allow DMZ outbound HTTP/HTTPS for updates

Action: Block | Interface: DMZ | Protocol: any
Source: DMZ net | Destination: any
Description: Default deny for DMZ

=== GUEST Rules ===
Action: Pass | Interface: GUEST | Protocol: TCP/UDP
Source: GUEST net | Destination: ! RFC1918_Networks | Port: 53, 80, 443
Description: Allow guest internet access only

Action: Block | Interface: GUEST | Protocol: any
Source: GUEST net | Destination: RFC1918_Networks
Description: Block guest Erişim: all internal networks

=== IOT Rules ===
Action: Pass | Interface: IOT | Protocol: TCP
Source: IOT net | Destination: ! RFC1918_Networks | Port: 443, 8883
Description: Allow IoT HTTPS and MQTT to cloud

Action: Block | Interface: IOT | Protocol: any
Source: IOT net | Destination: IOT net
Description: Prevent IoT lateral movement

Action: Block | Interface: IOT | Protocol: any
Source: IOT net | Destination: RFC1918_Networks
Description: Block IoT Erişim: internal
```

### Adım 5: Configure NAT Rules

```
Navigate: Firewall > NAT > Port Forward

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

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
Interface: WAN | Source: 10.10.10.0/24
Translation Address: <dedicated_public_ip>
Description: DMZ outbound NAT via dedicated IP
```

### Adım 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
```

### Adım 7: Backup and Test Configuration

```bash
Navigate: Diagnostics > Backup & Restore
Download XML configuration file

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)

curl -I https://www.google.com  # Should succeed (internet)
curl -I https://10.10.20.10     # Should fail (guest to internal blocked)

nslookup google.com 10.10.20.10  # Should succeed (DNS allowed)
ssh 10.10.1.50                    # Should fail (DMZ to LAN blocked)

Navigate: Status > System Logs > Firewall
Şunu kontrol et: blocked and passed traffic is logging correctly

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 Erişim: 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 Denetle:ion
- **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**:
1. Dağıt: pfSense on a Netgate 4100 appliance with four physical interfaces (WAN, LAN, DMZ, MGMT)
2. Create VLANs for staff (VLAN 10), EHR servers (VLAN 20), guest WiFi (VLAN 30), and medical devices (VLAN 40)
3. 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
4. Enable pfBlockerNG with healthcare-specific threat feeds and malware domain blocking
5. Configure outbound NAT to prevent internal IP addresses from leaking to the internet
6. Enable comprehensive logging and forward all firewall logs to a SIEM via syslog
7. Kur: automated configuration backups and Şunu belgele: 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)
```

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