A blocklist answer is a DNS answer

Answer A blocklist answer is a DNS answer. RFC 5782 describes how a DNS-based blocklist or allowlist works. A mail server looks up a name in the DNS. The name encodes an IP address or a domain. The answer comes back as DNS data. That data is the list's statement about the queried name at that moment. It is not a critique of your subject line, and it is not a census of solo ad sellers.

The note that started this: RFC 5782, DNS Blacklists and Whitelists, RFC 5782.

Buyers hear the word listed and freeze, or they hear the word clean and pay. Both reactions skip the query. Something was asked. Something answered. If you care about safe solo ads sellers, the next sentence is which name, which list, and what the seller did with the answer. A screenshot with a red mark and no name is a mood.

The document also covers the mirror idea, a DNS allowlist, where an answer means the list operator has chosen to vouch for a name. A vouch is still one operator's record. It is not a contract with the reader, and it is not a refund policy. Treat a friendly answer with the same habit you use for a hostile one. Write down the name that was queried.

What is a DNS blocklist answer?

RFC 5782 describes DNS-based lists. A mail server asks the DNS a question about an IP address or a domain name and gets an answer. The answer is about that query. It is not a review of the copy.

DNS is the system that turns names into answers. A blocklist that lives in the DNS is queried the same way other DNS data is queried. The mail server is not uploading your creative to a committee. It is asking a short question during the SMTP conversation, or around it, and branching on the reply. The reply can mean listed, or not listed, according to that list's own convention. This note will not invent the conventions. They differ by list, and a buyer who memorizes one list's codes and applies them to every list will misread the next answer.

That is why the seller's job is translation, in plain words. They should be able to say the IP or the domain, the list, the time, and the action they took. If the action was to keep mailing the same way, they should say that too. Silence plus a promise of inbox is not a translation.

• The name that was queried is written down.
• The list that answered is named.
• The creative is discussed as the creative, in a separate sentence.
• One list's silence is not written up as a certificate.

Does a blocklist hit mean the solo ad creative was the problem?

No. The list answers a question about an address on the network, usually the sending IP or a domain. The creative can be fine and the IP can still be listed. Ask which name was queried and which list answered.

Operators list names for reasons that have nothing to do with the paragraph you wrote this morning. A neighbor on a shared range can poison a neighborhood. A domain can be listed for mail you did not send. A creative can also be the reason people complain, and complaints can feed a listing later. The point of separating the objects is so you do not fix the wrong one. Rewriting a decent offer because an IP was listed wastes the afternoon. Leaving a rotten offer in place because the IP looked clean wastes the money.

Ask the seller for the sending domain on your order before the mail goes. Then, if a listing shows up, you know which name was yours. A seller who will not name the domain before the send is asking you to diagnose a ghost.

Can a buyer use a blocklist to prove a seller is safe?

No. A DNS answer is one list's data at one moment. Absence from one list is not a certificate. Ask the seller which lists they watch and what they did the last time an answer came back listed.

Safety, for a buyer, is a stack of ordinary facts. The domain is theirs. The complaint address works. The refund line is in the order. The file is not a mystery decade. A DNS answer can be one input to that stack. It cannot replace the stack. A seller who leads with a green dashboard and will not name a list is selling the color.

RFC 5782 is a description of a query. Use it that way. When someone says listed or clean, ask for the query. The answer is a DNS answer. Your decision to pay is still yours.