By ThreatListPro Security Team · Published February 27, 2026 · Last verified: February 28, 2026

When you decide to block malicious IPs at your firewall, the first question is: where do you get the list? The market ranges from free, community-maintained lists all the way up to six-figure enterprise threat intelligence platforms. Spending too little leaves gaps in coverage; spending too much wastes budget on capabilities you do not need.

This guide compares three tiers of IP threat intelligence—free open-source lists, curated blocklists like ThreatListPro, and enterprise threat feeds—so you can make an informed decision based on your actual security requirements and budget.

The Three Tiers at a Glance

Feature Free Open-Source $9.99/mo ThreatListPro $50-200+/mo Enterprise
Examples FireHOL, ipsum, Spamhaus DROP ThreatListPro Blocklist Palo Alto PAN-DB, CrowdStrike, Recorded Future
IP Count 100K to millions ~1,600 curated 10K to millions
Focus General threats (spam, scanning, C2) VPN brute force attacks Broad threat landscape
Update Frequency Varies (daily to monthly) Weekly Real-time to daily
False Positive Risk High (CDNs, cloud IPs) Low (curated, VPN-specific) Low to moderate
Firewall Compatibility Usually (may need reformatting) All major firewalls (EDL-ready) Vendor-specific integrations
SLA / Support None Email support, uptime guarantee Full SLA, dedicated support
Setup Time 30 min to hours (scripting needed) 5 minutes Hours to days

Tier 1: Free Open-Source Lists

The most well-known free IP lists include FireHOL (aggregates dozens of threat feeds into tiered block lists), ipsum (a GitHub-hosted list scoring IPs by how many blocklists they appear on), and Spamhaus DROP/EDROP (hijacked IP blocks used by spammers and criminals).

These lists are valuable community resources, but they come with significant operational challenges when used for VPN protection:

Advantages

  • Completely free
  • Large coverage (millions of IPs)
  • Community maintained and transparent
  • Good for general-purpose blocking

Drawbacks

  • Not focused on VPN attacks specifically
  • High false positive rates (block CDNs, cloud IPs, legitimate hosts)
  • Lists can exceed firewall entry limits
  • Stale entries remain for months or years
  • No SLA—list can go offline without warning
  • May need scripting to convert formats
  • No support when something breaks

The core problem with free lists for VPN protection is that they are not designed for this use case. FireHOL Level 1 contains tens of thousands of IPs involved in all types of malicious activity—spam, malware distribution, scanning, command-and-control. Many of these IPs have never attempted a single VPN login. Meanwhile, the VPN brute force IPs you actually need to block may not appear in these lists at all, because they focus on different threat categories.

Size matters: Loading a million IPs into a firewall EDL may exceed your device’s capacity, and even if it does not, blocking that many addresses dramatically increases the chance of collateral damage to legitimate traffic.

Tier 2: Curated Blocklist (ThreatListPro)

ThreatListPro occupies the middle ground: a paid service focused specifically on VPN brute force threats, priced for small and mid-size IT teams at $9.99 per month.

The blocklist is built from a network of honeypots that mimic GlobalProtect, SSL-VPN, and AnyConnect portals. Every IP on the list has been observed actively attacking VPN infrastructure within the past 30 days. IPs that stop attacking are removed, keeping the list current and compact—typically around 1,600 entries.

Advantages

  • Purpose-built for VPN brute force protection
  • Curated: every IP has been verified as an active attacker
  • Small list (~1,600 IPs) works on every firewall model
  • EDL-ready format: plug the URL into your firewall and go
  • Weekly updates with stale IP removal
  • 5-minute setup, zero ongoing maintenance
  • $9.99/mo fits any budget

Limitations

  • Focused only on VPN/authentication attacks
  • Does not cover malware, C2, or other threat categories
  • Weekly updates (not real-time)
  • No STIX/TAXII or SIEM integration
  • No threat actor attribution or contextual intelligence
ThreatListPro is designed for the IT administrator or small security team that has a specific, immediate problem—VPN brute force attacks—and needs a solution that works today without requiring a threat intelligence analyst to manage it.

Tier 3: Enterprise Threat Intelligence Feeds

At the enterprise level, vendors like Palo Alto Networks (PAN-DB, AutoFocus), CrowdStrike (Falcon Intelligence), Recorded Future, Mandiant Advantage, and Anomali offer comprehensive threat intelligence platforms with IP indicators, domain feeds, malware hashes, threat actor profiles, and integration with SIEMs and SOAR platforms.

Pricing varies widely. Entry-level commercial feeds start around $50 to $200 per month, but full enterprise platforms typically cost $10,000 to $100,000+ per year depending on the depth of intelligence, number of integrations, and level of support.

Advantages

  • Broad coverage across all threat categories
  • Real-time or near-real-time updates
  • Contextual intelligence (attribution, confidence, TTPs)
  • STIX/TAXII and API integrations
  • Full SLAs and dedicated support
  • Feeds into SIEM, SOAR, and EDR workflows

Drawbacks

  • Expensive ($50–200/mo minimum, enterprise tiers much more)
  • Requires dedicated staff to operationalize
  • General-purpose: may not prioritize VPN threats
  • Complex integration and configuration
  • Vendor lock-in with proprietary formats
  • Overkill for single-problem use cases

Enterprise feeds are the right choice for organizations with a dedicated security operations center (SOC) that needs intelligence across the full threat landscape. If you have analysts who will use the contextual data to conduct investigations and hunt for threats, the investment pays for itself. If you just need to block VPN attackers at your firewall, you are paying for capabilities you will never use.

When Each Tier Makes Sense

Choose free open-source lists when:

Choose ThreatListPro ($9.99/mo) when:

Choose enterprise threat feeds ($50-200+/mo) when:

Not mutually exclusive: Many organizations use ThreatListPro alongside an enterprise feed—the curated VPN-specific list provides precision blocking for the most urgent threat, while the enterprise feed covers the broader landscape.

Frequently Asked Questions

What is the difference between a blocklist and a threat feed?

A blocklist is a simple list of IP addresses designed to be loaded into a firewall for automated blocking. A threat feed is a broader intelligence product that may include IPs, domains, URLs, file hashes, and contextual information like threat actor attribution and confidence scores. Blocklists are action-oriented; threat feeds are intelligence-oriented. For VPN protection, a focused blocklist is more practical and easier to deploy.

Are free IP blocklists safe to use on a firewall?

Free lists like FireHOL and ipsum are useful starting points, but they carry risks for production use. They often contain millions of IPs, many of which are stale or belong to shared infrastructure like CDNs and cloud providers. Blocking these can disrupt legitimate traffic. Free lists lack SLAs for uptime or accuracy. For protecting critical infrastructure like VPN portals, a curated list with quality control is strongly recommended.

How much does a threat intelligence feed cost?

Free open-source lists cost nothing. Curated blocklists like ThreatListPro cost $9.99 per month. Commercial threat intelligence feeds start at $50 to $200+ per month for basic tiers, with full enterprise platforms costing $10,000 to $100,000+ per year depending on data volume, integrations, and support.

Can I use multiple blocklists at the same time?

Yes. Most firewalls support multiple EDLs simultaneously. You could use ThreatListPro for VPN threats and a separate list for broader indicators. Be mindful of your firewall’s total entry limit across all EDLs, and watch for overlap between lists, which wastes capacity.