What free tools can I use to check if my sender IP is blacklisted?

11 Marketer opinions 3 Expert opinions 4 Technical articles 3 Resources

Summary

Numerous free tools and methods are available to check if a sender IP is blacklisted. These include online blacklist checkers like MXToolbox, MultiRBL, WhatIsMyIP, UltraTools, HetrixTools, BlacklistAlert, DNSQueries, and Spamhaus. These tools query various DNS Blacklists (DNSBLs) and SURBLs. Some offer reputation monitoring (Talos Intelligence, SenderScore) or continuous monitoring. Documentation from providers like DigitalOcean, Barracuda Networks, and Spamcop detail the role of RBLs and provide checking tools. Experts also suggest analyzing email server logs or creating custom tools.

Key findings

Abundant Free Tools: A large number of free online tools enable checking IP addresses against multiple blacklists.
Diverse Methods: Besides dedicated blacklist checkers, sender reputation scores and log analysis provide insights.
Monitoring vs. Checks: Tools offer both one-time checks and continuous monitoring for blacklisting.
RBL Importance: Real-time Blackhole Lists (RBLs) or DNSBLs are crucial in identifying and blocking spam.

Key considerations

Accuracy Variance: The accuracy and completeness of blacklist checks vary; using multiple tools is recommended.
Proactive Monitoring: Continuous monitoring is more effective than occasional checks for maintaining deliverability.
Logistics of Logs: Analyzing server logs requires access and technical understanding.
Remediation Steps: If blacklisted, understanding the specific list's policies and remediation procedures is essential.
False Positives: Blacklist listings can be inaccurate; validation and appropriate action are needed.

What email marketers say
11Marketer opinions

Several free tools are available to check if a sender IP is blacklisted. These tools query various DNS blacklists (DNSBLs) and SURBLs to identify potential listings. Some tools offer manual checks, while others provide ongoing monitoring and alerts. In addition to blacklist-specific checkers, reputation monitoring tools and sender score services can provide insights into potential deliverability issues related to blacklisting.

Key opinions

Variety of Tools: A wide range of free online tools are available to check IP addresses against blacklists.
Manual vs. Monitoring: Some tools offer one-time manual checks, while others provide continuous monitoring and alerts for blacklisting.
Reputation Matters: Tools that assess sender reputation and scores can indirectly indicate blacklisting issues.
Multiple Check Sources: Different tools check against different sets of blacklists. Results may vary depending on the checker.

Key considerations

Tool Accuracy: The accuracy and comprehensiveness of blacklist checkers can vary; cross-referencing with multiple tools is advisable.
Proactive Monitoring: Ongoing monitoring is more beneficial than ad-hoc checks for maintaining deliverability.
Reputation Impact: Maintaining a positive sender reputation is crucial to avoid blacklisting and improve email deliverability.
False Positives: Blacklist listings are not always accurate. Further investigation is needed to determine if a listing is valid and to take appropriate remediation steps.

Marketer view

Email marketer from Reddit explains that you can use online tools like MXToolbox and BlacklistAlert to perform blacklist checks.

November 2023 - Reddit

Marketer view

Email marketer from BlacklistAlert answers that they have a free tool to check your IP against over 80 DNS blacklists. They also offer monitoring services.

February 2023 - BlacklistAlert

Marketer view

Email marketer from SenderScore shares that although not a direct blacklist checker, monitoring your sender score can indicate deliverability issues related to blacklisting. They offer a free tool to check your score.

October 2023 - SenderScore

Marketer view

Email marketer from Talos Intelligence shares that their free tool allows you to check the reputation of your IP address, which can indicate potential blacklisting issues.

July 2024 - Talos Intelligence

Marketer view

Email marketer from WhatIsMyIP mentions that they have a tool that will check your public IP address against multiple blacklists to see if it has been flagged for spam or other malicious activity.

May 2022 - WhatIsMyIP.com

Marketer view

Email marketer from HetrixTools suggests using their free blacklist checker which monitors your IPs against over 100 blacklists and notifies you of any listings.

March 2022 - HetrixTools

Marketer view

Email marketer from Email Geeks shares a free tool to manually check every IP - multirbl.valli.org, and advises to know what you’re looking at.

January 2023 - Email Geeks

Marketer view

Email marketer from MXToolbox explains that their free blacklist checker tool allows you to check your IP address against multiple DNS-based blacklists (DNSBLs) to see if it's listed.

July 2022 - MXToolbox

Marketer view

Email marketer from DNSQueries responds that they offer a free DNS blacklist lookup tool that allows you to check an IP address against multiple blacklists.

April 2022 - DNSQueries

Marketer view

Email marketer from UltraTools responds that they provide a free online tool to check if your IP address or domain is blacklisted by querying various DNSBLs and SURBLs.

January 2024 - UltraTools

Marketer view

Email marketer from Spamhaus shares that they offer a free IP and domain reputation checker on their website which allows you to check if your sender IP is listed on their blocklists.

February 2022 - Spamhaus

What the experts say
3Expert opinions

Experts suggest using blacklist check tools (such as MXToolbox and MultiRBL) to check your IP against multiple blacklists simultaneously. Another method is to create your own tool or check your logs for blocks mentioning blocklists to quickly discover blocks.

Key opinions

Multiple Approaches: Several approaches can be used to check if your sender IP is blacklisted, including using existing online tools or creating your own.
Log Analysis: Checking your email server logs for blocks mentioning blocklists is a fast way to discover a block.
Online Tools: Several online blacklist check tools like MXToolbox and MultiRBL provide the capability to check your IP against multiple blacklists at once.

Key considerations

Tool Choice: Consider the specific features and reliability of different online blacklist check tools before selecting one.
Log Access: Access to and understanding of your email server logs are necessary for using the log analysis method.
Custom Tool Development: Creating your own tool requires technical expertise and resources.

Expert view

Expert from Wordtothewise.com shares that there are several blacklist check tools available, such as MXToolbox and MultiRBL, that allow you to check your IP address against multiple blacklists simultaneously.

April 2021 - Wordtothewise.com

Expert view

Expert from Email Geeks shares that you can create your own tool or check your logs for blocks that mention blocklists as a fast way to discover a block.

January 2025 - Email Geeks

Expert view

Expert from Spamresource.com explains that using a blacklist check tool is a good method to see if you have been added to a blacklist. They suggest using their tool or similar online tools.

June 2024 - Spamresource.com

What the documentation says
4Technical articles

Various documentation sources highlight the use of Real-time Blackhole Lists (RBLs), also known as DNSBLs, to combat spam. These lists contain IP addresses known to send spam. Free online tools and services, like MultiRBL, Barracuda Networks' RBL, and Spamcop, can be used to check if an IP address is listed on these blacklists.

Key findings

RBLs as Spam Defense: SMTP blacklists (RBLs/DNSBLs) are a common and effective method for identifying and blocking spam.
Free Checkers Available: Multiple free services exist that allow you to check if your IP is listed on various RBLs.
Source Variety: Different organizations (e.g., MultiRBL, Barracuda, Spamcop) maintain their own RBLs and offer checking tools.

Key considerations

List Differences: Each RBL operates independently, so being listed on one doesn't necessarily mean you're listed on all.
False Positives: Listings can sometimes be inaccurate; further investigation may be needed to determine validity.
Remediation: If listed, understand the listing policy and follow the proper remediation steps to get removed.

Technical article

Documentation from DigitalOcean explains that SMTP blacklists (DNSBLs) are a common tool for fighting spam. They list IPs known to send spam. You can check your server's IP against these lists using online tools.

March 2022 - DigitalOcean

Technical article

Documentation from Barracuda Networks explains that their RBL (Reputation Block List) is a real-time database of IP addresses known for sending spam. They also have tools that you can use to check if you are on their list.

October 2023 - Barracuda Networks

Technical article

Documentation from Spamcop explains that their free service identifies and blocks spam. You can check if your IP is listed on their blocklist through their website.

May 2021 - Spamcop

Technical article

Documentation from MultiRBL provides a free service that allows you to check an IP address against multiple RBLs (Real-time Blackhole Lists) at once.

September 2024 - MultiRBL.valli.org

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