The NoSolicitado Worst Blacklist is a specialized IP-based blocklist targeting the most severe spammers and phishing attempts, with a particular focus on Spanish-language unsolicited email, making it a highly accurate blacklist with a goal of zero false positives.
The NoSolicitado Worst Blacklist, with the zone name bl.worst.nosolicitado.org, is an IP-based DNS blocklist (DNSBL) designed to stop the most egregious spammers. Its operators state that it has a policy of zero false positives, focusing only on IP addresses with a clear and significant history of sending unsolicited email. If you are on this blacklist, it's because NoSolicitado's systems have detected a high volume of spam originating from your mail server's IP address.
This blacklist or blocklist specifically targets servers sending spam, phishing attempts, scams, and other fraudulent emails. NoSolicitado employs spam traps, which are email addresses published on web pages to act as decoys. When a spammer harvests these addresses and sends email to them, it provides clear evidence of unsolicited activity, leading to a listing. The service is particularly focused on identifying unsolicited emails written in Spanish, which may not be caught by other systems like SpamAssassin.
A common reason for being listed is sharing an IP address with other domains on the same server. If even one of those domains engages in spamming, the entire shared IP can be added to the blocklist. According to NoSolicitado, some email servers with an extremely poor reputation will not be removed from the list.
The blacklist is operated by NoSolicitado.org, a Spanish-language RBL service. They see themselves as a key player in email security, handling over six billion queries per month. Their core philosophy is that blocklists are necessary because of irresponsible email service providers and datacenter operators who fail to prevent spam. By focusing on Spanish-language spam, they aim to fill a gap left by other prominent English-based blocklists, working to improve the email ecosystem for Spanish-speaking users.
If you are the administrator of a server listed on this blocklist, you can request removal. However, before you do so, you must identify and resolve the underlying issue that caused the listing. Simply requesting to be delisted without fixing the problem will likely result in being listed again.
Before requesting delisting, take the following steps:
Once you are confident the issue is resolved, you can use the official delisting form on the NoSolicitado website to request a review. Be aware that NoSolicitado states they reserve the right to ignore what they consider to be meritless disputes.
The impact of being on the NoSolicitado Worst Blacklist is considered medium. While it is used by thousands of servers handling billions of emails, its primary influence is within the Spanish-speaking community. If your audience is mainly in Spanish-speaking regions, a listing on this blacklist could cause significant deliverability problems, leading to a high number of bounced emails. For senders with a global or non-Spanish-speaking audience, the impact might be less severe but should still be addressed promptly to maintain a healthy sender reputation.
19 resources
Do blacklists exist for newly registered domain names?
How to interpret and assess unknown email blacklists like NoSolicitado?
Should I be concerned about the NoSolicitado blacklist for email sending?
Should I use blacklist or blocklist in email marketing?
What are examples of insignificant or ineffective email blocklists?
What common blocklists or services cause 'message rejected as spam' errors for ESPs?