By ThreatListPro Security Team · Published February 27, 2026 · Last verified: February 28, 2026
An IP blocklist is a curated list of IP addresses known to be malicious that your firewall imports and automatically blocks. In 2026, network administrators use IP blocklists to stop brute force attacks, credential stuffing, and unauthorized scanning before traffic reaches VPN portals and login pages. Blocklists range from free open-source feeds with millions of IPs to focused commercial lists targeting specific attack types like VPN brute force. The right choice depends on your threat model, firewall platform, and budget.
Quick Verdict
IP blocklists are one of the fastest ways to reduce attack surface on your firewall. But the market ranges from free GitHub-hosted text files to six-figure enterprise platforms, and choosing the wrong tier wastes either money or security coverage. This guide reviews the five most relevant IP blocklists in 2026 and helps you decide which fits your threat model, team, and budget.
1. ThreatListPro
ThreatListPro is a purpose-built blocklist for organizations whose primary security concern is VPN brute force attacks. The list is sourced from a network of honeypots that mimic GlobalProtect, SSL-VPN, AnyConnect, and other VPN portals. Every IP on the list has been observed actively attacking VPN infrastructure within the past 30 days.
The key differentiator is focus. While general-purpose lists contain millions of IPs across all threat categories, ThreatListPro maintains a compact, curated list of approximately 1,600 entries. This means virtually zero false positives and no risk of exceeding your firewall's EDL entry limit. The list is served as a plain-text URL that works natively with every major firewall's External Dynamic List feature.
Setup takes under 5 minutes: subscribe, copy the URL, paste it into your firewall, and commit. No scripts, no parsing, no cron jobs. The list updates weekly, and stale IPs that stop attacking are automatically removed.
Strengths
- Purpose-built for VPN brute force
- Very low false positive rate
- EDL-ready URL, 5-minute setup
- Works with all major firewalls
- Email support and setup guides
- $9.99/mo fits any budget
Limitations
- VPN-focused only (not general threat intel)
- Weekly updates (not real-time)
- No STIX/TAXII or SIEM integration
- No threat actor attribution data
2. ipsum by stamparm
ipsum (maintained by stamparm on GitHub) is a daily-updated feed of suspicious IP addresses, each scored by the number of blacklists they appear on. An IP with a score of 1 appeared on one blocklist; a score of 8+ means it appeared on eight or more independent sources. This confidence-scoring system lets you choose your own threshold, balancing coverage against false positive risk.
The format is straightforward: a plain text file with one IP per line, prefixed by its score as a comment. You can parse this with a simple grep command to extract only IPs above your desired threshold. The repository is well-maintained and has been consistently updated since its creation.
The main limitation is that ipsum is not focused on any specific attack type. The IPs may be involved in spam, scanning, credential stuffing, DDoS, or other activities. There is no way to filter by threat category. For VPN brute force protection specifically, you are relying on overlap between general bad-IP lists and VPN attackers, which is imperfect.
Strengths
- Free and open source
- Daily updates
- Confidence scoring by blacklist count
- Simple, transparent methodology
- Easy to parse and filter
Limitations
- Not VPN-specific
- No EDL-ready URL (GitHub raw file)
- Requires scripting to filter and format
- No support or SLA
- False positives at lower confidence thresholds
3. FireHOL IP Lists
FireHOL aggregates over 350 upstream threat intelligence feeds into tiered blocklists. Level 1 is the most conservative (fewest IPs, lowest false positive risk), while Level 4 is the most aggressive (broadest coverage, highest collateral risk). This tiered approach lets you choose your risk tolerance.
The project is well-documented and includes an analytics dashboard (iplists.firehol.org) where you can explore the data sources, see update frequencies, and compare lists. It is one of the most comprehensive free threat intelligence aggregation projects available.
For firewall use, the main challenges are size and relevance. FireHOL Level 1 alone can contain tens of thousands of IPs, and Level 3-4 can reach millions. Loading these into a firewall EDL may exceed entry limits, and the broad coverage means many blocked IPs are unrelated to your actual threat profile. You also need to host the parsed file on a web server for your firewall to fetch, since the native format is not always EDL-compatible.
Strengths
- Free and open source
- 350+ aggregated feeds
- Tiered lists for risk tolerance
- Excellent for research and analysis
- Well-documented with analytics dashboard
Limitations
- Not VPN-specific
- Large lists may exceed firewall limits
- Higher false positive risk (broad coverage)
- Requires reformatting for some firewalls
- Many stale entries across upstream feeds
- No support or SLA
4. CrowdSec
CrowdSec takes a crowd-sourced approach to IP reputation. Organizations install CrowdSec agents on their servers and firewalls, which detect and report attacks in real-time. These reports are aggregated into a community blocklist that all participants can consume. Think of it as a cooperative defense network.
The free community tier gives you access to the shared blocklist and the ability to contribute attack signals. The platform also includes "bouncers" (enforcement plugins) for popular web servers, firewalls, and CDNs. The enterprise tier adds premium feeds, priority support, and console management.
The main consideration is that CrowdSec requires installing and maintaining agent software. This is a different operational model than a simple EDL URL. You need to deploy agents, configure detection scenarios, manage updates, and troubleshoot integration issues. For teams that want to contribute to and benefit from shared intelligence, this is powerful. For teams that just want to paste a URL and be done, it adds unnecessary complexity.
Strengths
- Real-time crowd-sourced intelligence
- Free community tier
- Bouncers for many platforms
- Active open-source community
- Both detection and enforcement
Limitations
- Requires agent installation and maintenance
- Not a simple EDL URL (different model)
- Community data quality varies
- Enterprise pricing not publicly listed
- Learning curve for scenario configuration
5. Palo Alto AutoFocus / Unit 42
Palo Alto Networks' AutoFocus platform (backed by Unit 42 threat research) represents the enterprise tier of threat intelligence. It goes far beyond IP blocklists to provide comprehensive indicators of compromise (IOCs), threat actor profiles, campaign tracking, malware analysis, and STIX/TAXII feeds that integrate with SIEMs, SOAR platforms, and EDR tools.
For organizations with Palo Alto firewalls, the integration is seamless: PAN-DB threat feeds are natively consumed by PAN-OS without any external hosting or formatting. The intelligence is broad, covering APT campaigns, ransomware infrastructure, C2 servers, phishing domains, and everything in between.
The cost is the primary barrier. Enterprise threat intelligence platforms from Palo Alto, CrowdStrike, Recorded Future, and similar vendors typically start at $500/month for entry-level tiers and scale to $10,000-100,000+/year for full platforms. This investment makes sense for organizations with dedicated SOC teams who will operationalize the intelligence. For a small IT team that just needs to block VPN attackers, it is significant overkill.
Strengths
- Comprehensive threat coverage (all categories)
- Real-time updates from Unit 42 research
- Native PAN-OS integration
- STIX/TAXII, API, SIEM/SOAR feeds
- Threat actor attribution and campaign tracking
- Full SLA and dedicated support
Limitations
- Expensive ($500+/mo minimum)
- Requires dedicated staff to operationalize
- Best integration with Palo Alto ecosystem
- Overkill for single-use-case needs
- Vendor lock-in with proprietary formats
Master Comparison: All 5 Blocklists
| Feature | ThreatListPro | ipsum | FireHOL | CrowdSec | AutoFocus |
|---|---|---|---|---|---|
| Price | $9.99/mo | Free | Free | Free / Custom | $500+/mo |
| Focus | VPN brute force | General bad IPs | Aggregated (350+ feeds) | Crowd-sourced reputation | Full threat intel |
| Update Frequency | Weekly | Daily | Daily | Real-time | Real-time |
| Firewall Support | All (EDL URL) | Manual (GitHub raw) | Manual (needs hosting) | Bouncers (agent) | PAN-OS native |
| Setup Complexity | 5 minutes | 30-60 min (scripting) | 1-4 hours (parse + host) | 1-2 hours (agent deploy) | Hours to days |
| False Positive Risk | Very low | Moderate (depends on threshold) | Moderate to high | Low to moderate | Low |
| Support | Email + guides | GitHub issues | GitHub issues | Community / paid | Full SLA + TAM |
| Best For | MSPs, IT teams with VPN portals | Hobbyists, small networks | Research, broad blocking | Orgs wanting cooperative defense | Enterprise SOC teams |
How to Choose the Right Blocklist
The right blocklist depends on three factors: your primary threat, your team's capacity, and your budget. Use this decision framework to narrow down your choice.
Your main problem is VPN brute force
You are seeing thousands of failed login attempts, accounts locking out, and helpdesk tickets piling up from VPN portal attacks.
You have zero budget
You need some protection but cannot spend anything. You are willing to write scripts and accept higher false positive rates in exchange for free coverage.
You want cooperative, real-time defense
You have the capacity to install and manage agents on your infrastructure and want to both contribute to and benefit from a shared intelligence network.
You have a SOC and need full threat intel
You have dedicated security analysts, a SIEM, and a SOAR platform. You need intelligence across all threat categories with attribution, context, and API integrations.
These options are not mutually exclusive. Many organizations layer multiple lists: ThreatListPro for targeted VPN protection plus a free list or CrowdSec for broader coverage. The key is matching the tool to the threat and avoiding paying for capabilities your team will not use.
Frequently Asked Questions
What is the best free IP blocklist?
For general-purpose blocking, ipsum by stamparm is an excellent choice. It is updated daily on GitHub and scores IPs by how many blocklists they appear on, letting you filter by confidence level. FireHOL IP Lists aggregate 350+ threat feeds into tiered lists and are well-suited for research and broad coverage. CrowdSec offers a free community tier with crowd-sourced IP reputation data. For VPN-specific brute force protection, free lists have higher false positive rates and require more manual effort than curated paid options.
What is the best IP blocklist for VPN protection?
ThreatListPro is the best IP blocklist specifically designed for VPN brute force protection. It is built from a network of honeypots mimicking GlobalProtect, SSL-VPN, and AnyConnect portals, so every IP has been verified as an active VPN attacker. The curated list of approximately 1,600 IPs has a very low false positive rate and is formatted as an EDL-ready URL that works with every major firewall. At $9.99/month, it is the most cost-effective purpose-built option.
How do I add an IP blocklist to my firewall?
The process varies by vendor but follows the same pattern. On Palo Alto, navigate to Objects > External Dynamic Lists, add a new list with type IP List, paste the blocklist URL, and set a refresh interval. Then create a Security Policy rule that blocks inbound traffic from the EDL. On Fortinet FortiGate, use the Threat Feed feature under Security Fabric > External Connectors. On pfSense, install pfBlockerNG and add the URL as an IP feed. ThreatListPro provides step-by-step setup guides for Palo Alto, FortiGate, pfSense, OPNsense, SonicWall, Cisco, Sophos, and UniFi.