Should I be concerned about the NoSolicitado blacklist for email sending?
Matthew Whittaker
Co-founder & CTO, Suped
Published 30 Jul 2025
Updated 19 Aug 2025
8 min read
When managing email deliverability, it is common to come across various blacklists or blocklists. A frequent question that arises is whether all of them warrant the same level of concern. One such list that occasionally pops up is NoSolicitado.org, an anti-spam project based in Spanish-speaking regions. Many email senders wonder if being listed on this particular blocklist should be a major concern for their email campaigns.
While any blacklist listing can cause a moment of panic, it is crucial to understand the specific nature and influence of each blocklist. Some blacklists have a broad impact on global email deliverability, while others are more niche or regional. I find that gaining a clear understanding of a blocklist's scope helps determine how urgently you need to address a listing.
NoSolicitado.org operates as a Real-time Blackhole List (RBL) or DNS-based Blackhole List (DNSBL). It primarily focuses on identifying and listing IP addresses that send unsolicited commercial email, often in Spanish. The organization achieves this by publishing email addresses on various pages, acting as decoys to capture spam. When an email server sends mail to one of these decoy addresses, its IP address may be added to the NoSolicitado blacklist.
The project's name, 'NoSolicitado,' directly translates to 'Unsolicited,' reflecting its mission to combat unwanted emails. Given its linguistic and regional focus, its influence is often more pronounced in Spanish-speaking countries, particularly within South America, as suggested by some email experts. This regional emphasis is a key factor when assessing its potential impact on your email program.
To understand how different blocklists function, you can consult an in-depth guide to email blocklists. It sheds light on how such lists impact email deliverability overall. Learning how email blacklists actually work can provide valuable context for navigating the complex world of sender reputation.
Impact on email deliverability
When assessing the importance of any email blacklist, the crucial question is whether it actually stops your mail from being delivered. While a NoSolicitado.org listing can be a symptom of underlying issues, its direct impact on major global mailbox providers is generally limited. Most large providers, like Google and Yahoo, primarily rely on their own internal reputation systems and a select few highly influential blacklists, such as Spamhaus.
However, some smaller or regional Internet Service Providers (ISPs), particularly in Latin America, might integrate data from blocklists like NoSolicitado.org into their filtering processes. This means that if your audience is heavily concentrated in those specific regions, a listing on this blocklist could indeed affect your deliverability to those recipients. For broader audiences, the direct effect is typically minimal. It is important to know what a DNSBL is and how it affects email deliverability in general.
Major global blocklists
These lists, such as Spamhaus, are widely used by mailbox providers globally and a listing here can severely impact your deliverability across the board. They have a significant influence on sender reputation and inbox placement for all types of emails.
Sometimes, smaller lists like SORBS might still be used by some European ISPs, but this is less common with major providers.
It is worth noting that the actions that lead to a blocklist listing, such as sending unsolicited emails or having poor list hygiene, can also independently damage your overall sender reputation with mailbox providers. So, even if the blocklist itself isn't directly consulted by a major ISP, the underlying bad sending practices will still lead to deliverability issues. Delisting from a minor blacklist will not magically fix these deeper reputation problems.
Assessing and addressing a listing
The most reliable way to determine if a NoSolicitado.org listing is affecting your email deliverability is to check your email sending logs. Look for bounce messages or rejections that specifically cite NoSolicitado.org as the reason. If your logs do not show rejections or deferrals mentioning this specific blocklist, its impact on your current sending is likely negligible. This direct observation is more valuable than merely checking if you appear on the list.
If you find that emails are indeed being blocked due to NoSolicitado.org, especially if you have a significant audience in Latin American regions, you should address the listing. The delisting process typically involves visiting their website, checking your IP or domain, and following their instructions to request removal. You can find their delisting page on the NoSolicitado.org BL Delisting page. It is vital to identify and fix the underlying issue that caused the listing in the first place, such as sending to unengaged recipients or compromised accounts.
Verify impact: Before taking action, confirm that the listing is actually causing delivery failures by checking your email logs.
Address root cause: Simply delisting without fixing the source of the problem, like poor list hygiene, will likely lead to re-listing or other reputation issues.
Regional relevance: Consider your target audience. If you do not send to Latin American regions, the impact may be minimal.
Understanding how to interpret and assess unknown email blacklists is a crucial skill for any sender. A listing on a less influential blocklist like NoSolicitado.org should prompt an investigation into why you were listed, but it should not necessarily trigger a full-blown panic unless it is actively causing delivery failures that you can confirm in your logs.
Maintaining a healthy sender reputation
The most effective way to prevent listings on NoSolicitado.org, or any blacklist (or blocklist), is to adhere to email sending best practices. This includes maintaining clean, opt-in email lists, avoiding sending to unengaged recipients, and promptly removing bounces and inactive addresses. Sending only to people who have subscribed is perhaps the simplest and most crucial step.
Regularly monitoring your email deliverability metrics and bounce logs can help you proactively identify potential issues before they escalate into widespread blocklist (or blacklist) listings. Tools that provide an email deliverability test can be invaluable. Remember that the goal is not just to get off a blacklist, but to prevent getting on them in the first place by fostering a strong sender reputation.
The overall health of your sending infrastructure and practices plays a much larger role in deliverability than a listing on a niche blocklist. If your IP address is blacklisted on a major list, or if your sending behavior indicates spammy activity, that is where your focus should lie. Fixing fundamental issues like high spam complaints, sending to purchased lists, or poor email authentication (SPF, DKIM, DMARC) will have a far greater positive impact than solely addressing minor blocklist entries.
In essence, while it is good to be aware of NoSolicitado.org, it is rarely a primary concern for most senders unless they specifically target audiences heavily influenced by its listings. Your efforts are better spent on maintaining robust sender authentication, managing clean and engaged lists, and consistently monitoring your overall deliverability, which are key to boosting email deliverability rates across the board. If you are ever asking yourself why your emails are going to spam, consider the broader factors first.
Views from the trenches
Best practices
Always prioritize maintaining a clean, opt-in email list to avoid attracting the attention of blacklists (or blocklists).
Focus your monitoring efforts on major, globally influential blacklists like Spamhaus for maximum impact on deliverability.
Regularly check your email sending logs for specific bounce messages indicating a blocklist (or blacklist) listing.
Address the root cause of any listing, rather than just seeking delisting, to improve overall sender reputation.
Implement and maintain strong email authentication protocols, including SPF, DKIM, and DMARC.
Common pitfalls
Overreacting to listings on minor or regional blocklists (or blacklists) that have limited global impact.
Neglecting to check email logs for concrete evidence of delivery issues caused by a blocklist (or blacklist) listing.
Attempting to delist an IP without first identifying and resolving the underlying sending problem.
Assuming that being listed on one blacklist (or blocklist) automatically means all mail will be blocked by all providers.
Failing to adapt sending strategies based on audience geography and local email filtering norms.
Expert tips
Most major mailbox providers do not secretly use publicly available blocklists (or blacklists), with Spamhaus being a notable exception.
The actions that get you listed on a blocklist often also decrease your reputation with providers, even if they don't use that specific list.
Delisting from a blocklist does not automatically fix underlying sender reputation issues with mailbox providers.
Some European ISPs might still use data from certain smaller blacklists (or blocklists) for reputation classification, so be aware of your target regions.
Always verify if a blocklist (or blacklist) listing is actually impacting your mail delivery before taking significant action.
Expert view
Expert from Email Geeks says that if you are mailing into some parts of South America, NoSolicitado might be a concern, but the best measure of whether to care about a blocklist is if it stops your mail from being delivered.
2020-02-09 - Email Geeks
Marketer view
Marketer from Email Geeks says that the main concern with blacklists is their correlation with other random blocks or if mail providers share findings. NoSolicitado.org is generally a small regional list, so if mail delivery is not directly affected, it is fine. However, delisting and identifying the cause is always recommended.
2020-02-10 - Email Geeks
Final thoughts on NoSolicitado.org
In summary, while NoSolicitado.org is a legitimate anti-spam blacklist, its impact is largely regional, primarily affecting email deliverability in specific Spanish-speaking territories, especially within South America. For most email senders with a global audience, a listing on this blocklist is less critical than those on widely adopted lists like Spamhaus.
The key takeaway is to prioritize verifying if the listing is actually causing delivery issues in your email logs. If it is, especially for relevant audiences, address it by fixing the root cause of the problem and then initiating the delisting process. Ultimately, a proactive approach to email sending best practices and consistent deliverability monitoring remains your best defense against any blocklist, ensuring your emails reliably reach the inbox.
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technoirc.org
TechTheft
Google and 
Yahoo, primarily rely on their own internal reputation systems and a select few highly influential blacklists, such as Spamhaus.
Spamhaus, are widely used by mailbox providers globally and a listing here can severely impact your deliverability across the board. They have a significant influence on sender reputation and inbox placement for all types of emails.
