Best Quad9 Alternatives & Competitors in 2026

HYAS Protect Protective DNS

Protective DNS solution that blocks malicious domains and prevents cyber attacks

BlueCat Edge

DNS-layer security solution for threat detection and policy enforcement

DNSSense DNSDome

AI-based DNS security platform blocking tunneling, malware, and zero-days.

threatER

Preemptive threat blocking platform using IP segmentation and DNS security.

Wireless Airspace Cybersecurity Platform

AI-driven RF monitoring platform for wireless device detection & threat mgmt.

Trellix Intrusion Prevention System

Next-gen IPS detecting & blocking network threats via signatures & behavior

Palo Alto Networks Advanced Threat Prevention

IPS with inline AI models to block zero-day exploits and C2 attacks in real time

Snort Open Source

Snort is an open-source network intrusion detection and prevention system that analyzes traffic in real-time to identify and block malicious activity using rule-based detection methods.

ThreatSTOP Protective DNS

DNS-layer threat blocking service with real-time threat intelligence feeds

Infoblox Threat Defense

DNS-based threat defense using predictive intelligence to block threats

Trend Micro TippingPoint Threat Protection System

Inline network detection and response system with IPS capabilities

Palo Alto Networks Advanced DNS Security

DNS security service that blocks DNS-layer threats in real time

Cybermerc Aushield Protect

Network security solution for SMBs with behavioral intrusion detection

OpenText Core DNS Protection

Cloud-native DNS filtering solution that blocks malicious domains and threats

ScoutDNS Threat Protection

DNS-layer threat protection blocking malware, phishing, and DNS attacks

Backbox Network Cyber Resilience Platform

Network infrastructure automation platform for cyber resilience tasks

Akheros

Anomaly-based IDS using relative incongruity scoring to reduce false positives.

Axiom Cyber HakTrap

Hardware network security device for home/SMB with continuous threat updates.

Centripetal CleanINTERNET®

Real-time network threat prevention platform enforcing 10B+ threat indicators.

Digital Arts Inc.

Japanese cybersecurity firm offering web/email filtering & data loss prevention.

Guardian360 Hacker Alert

24/7 network intrusion detection with immediate alert notifications.

IDappcom TrafficIQ Professional

Windows platform for auditing network security defences via custom PCAP replay.

Whalebone

DNS-based cybersecurity platform for telcos, ISPs, enterprises & govts.

Intrusion Shield

Network threat protection platform blocking malicious IPs using reputation intelligence.

Trapster Community

A low-interaction honeypot that simulates network services to detect intrusion attempts

Defensia

Open-source Linux security agent with real-time dashboard: SSH, WAF, and CVE scanning

Fail2ban

Fail2ban is a daemon that automatically bans IP addresses showing malicious behavior by monitoring log files and updating firewall rules to prevent brute-force attacks.

CrowdSec Security Stack

Open source crowd-powered IDS/IPS and WAF for infra & app security.

Suricata

Suricata offers real-time intrusion detection, intrusion prevention, and network monitoring.

Bro IDS

An open-source network security monitoring tool.

CrowdSec

CrowdSec is a collaborative behavior detection engine that analyzes system logs to identify and block malicious activities using community-shared threat intelligence.

Kismet

A wireless network detector, sniffer, and intrusion detection system

SSHWATCH v2.0 Intrusion Prevention System (IPS) for Secure Shell (SSH)

An intrusion prevention system for SSH that blocks IP addresses after a set number of consecutive failed login attempts.

Vanguards Onion Service Addon

A controller addon that provides additional security defenses for onion services ahead of official Tor-core release.

6Guard (IPv6 attack detector)

6Guard is an IPv6 attack detector sponsored by Google Summer of Code 2012 and supported by The Honeynet Project organization.

Snort++

Snort 3 is the next generation Snort IPS with enhanced features and improved cross-platform support.

DenyHosts

DenyHosts is a script to block SSH server attacks by automatically preventing attackers after failed login attempts.

libnids

Libnids is an implementation of an E-component of Network Intrusion Detection System that emulates the IP stack of Linux 2.0.x and offers IP defragmentation, TCP stream assembly, and TCP port scan detection.

Haka

Open source security-oriented language for describing protocols and applying security policies on captured traffic.

SSHGuard

SSHGuard protects hosts from brute-force attacks by monitoring system logs, detecting attacks, and blocking attackers using a firewall.

BPF+: Exploiting Global Data-flow Optimization in a Generalized Packet Filter Architecture

BPF+ is a generalized packet filter framework that achieves both high-level expressiveness and good performance for network monitoring and intrusion detection applications.