The SpamRATS RATS NoPtr Blacklist is an IP-based blocklist that identifies mail servers sending abusive connections or sending to too many invalid users while also lacking a proper reverse DNS/PTR record.
The SpamRATS RATS NoPtr Blacklist is an IP-based blocklist that specifically targets IP addresses that do not have a valid reverse DNS or Pointer (PTR) record. This blacklist (or blocklist) is populated by IPs that exhibit abusive behavior, such as sending an excessive number of connections or attempting to deliver emails to a high volume of invalid user accounts at ISP and Telco mail servers. The lack of a PTR record is a key characteristic for this listing.
According to established best practices for network and email operators, any IP address running a mail server should have a correctly configured PTR record. This record helps identify the party responsible for the mail server. An IP address that is sending a flood of connections without a PTR record is often a strong indicator of a compromised machine or an improperly configured server, which contributes significantly to wasted overhead for receiving mail servers. The RATS NoPtr blacklist contains IPs on networks known to permit outbound traffic on port 25 from addresses lacking a reverse DNS record.
SpamRATS runs the RATS NoPtr blocklist. SpamRATS is an established provider of IP reputation lists, offering Real-time Blackhole List (RBL) services and data feeds. With threat data spanning over 15 years, it positions itself as a reliable source of threat intelligence. The organization provides several different IP reputation lists to cater to various security and filtering needs.
To get delisted from the SpamRATS RATS NoPtr blacklist, you must first resolve the underlying issue. This blocklist specifically targets IPs without a valid PTR record, so you will only be able to request removal after you have correctly configured the reverse DNS for your IP address. It is important that the PTR record accurately reflects who is responsible for operating the mail server.
The impact of being listed on the SpamRATS RATS NoPtr blacklist is generally considered low. This specific blacklist is not as widely used as some of the larger, more impactful blocklists in the industry. However, any blacklist inclusion can negatively affect your email deliverability. Mail servers and systems that do use this list will likely reject your emails, leading to bounces and preventing your messages from reaching the inbox. It is always a best practice to resolve any blacklist or blocklist listing promptly to maintain a healthy sender reputation.
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