A path that works on one network is not a path that works on both.

Answer A path that works on one network is not a path that works on both. RFC 3974 is an experience report about SMTP when IPv4 and IPv6 are mixed. The document is RFC 3974, titled SMTP Operational Experience in Mixed IPv4/v6 Environments. It is not a census and not a solo result. Someone wrote down operational experience. That write-up does not count your readers, and it does not show that a route which worked on one network also worked on the other. A story about mixed networks is not your send.

Cream stationery and a teal accent on a dark navy desk — One working path is not a promise about the other.

The note that started this: RFC 3974, SMTP Operational Experience in Mixed IPv4/v6 Environments, RFC 3974.

Buyers hear worked once and stretch it to worked everywhere. The stretch is the mistake. If you are about to buy solo ads, ask the seller which path the order claims, and ask what they will say if a path works on only one of the two. A shrug means the pitch is using a public report as a blanket. A blanket is not a list, and it is not a letter.

That is a fact about mail software or about an old specification. It is not a solo ad price, a rank, or proof that a stranger opted in. A buyer still has to name the list, the sending domain, and the refund line on the order. An experience report fills none of those blanks. A seller who opens with the report and never names the list is handing you a public document and calling it a result. Read the document if you want. Pay only for the order.

What does RFC 3974 describe?

RFC 3974 is an experience report about SMTP when IPv4 and IPv6 are mixed. The document is RFC 3974, titled SMTP Operational Experience in Mixed IPv4/v6 Environments. It is not a census and not a solo result.

An experience report tells what people ran into while operating mail on mixed networks. It is not a headcount of inboxes. It is not a scoreboard for a solo ad. You can learn that mixed networks are a real operational topic and still learn nothing about the list you are about to rent. The seller who slides the report across the desk as proof the send lands for everyone has changed the subject. The subject is the order.

Ask a narrower question than the report can answer. Which list, which sending domain, and what does the refund line say if the path you were shown is not the path the readers are on? Those questions fit on an order. The report does not answer them, because it was not written as your invoice. A buyer who treats one working path as both paths is buying a hope. A seller who encourages that hope should expect the refund conversation the order already named.

The order does not claim both networks because one path worked.
The report is not called a census of readers.
The list, the sending domain, and the refund line are named.
A solo result is not borrowed from an experience note.

Does a path that works on one network work on both?

No. A path that works on one network is not a path that works on both. The report talks about mixed networks. It does not prove your send reaches both.

Keep the two networks separate in your notes even if you never touch the machinery. Separate means you do not let a success on one stand in for the other. You also do not invent a duty to explain the machinery. You only refuse the slogan. If the seller cannot describe the claim without pointing at the report, the claim is not about your buy. It is about a document anyone can read.

If you have not paid, do not pay for coverage the order cannot name. If you have paid and the proof of coverage was one path plus this report, the refund line is the next sentence. On the seller side, say which path you mean. Say that the other path is a different fact. A careful seller would rather lose the order than let one working route impersonate both. The impersonation feels clever until the buyer asks who actually got the letter.

Does the experience report prove opt-in?

No. That is a fact about mail software or about an old specification. It is not a solo ad price, a rank, or proof that a stranger opted in.

Operational experience is not a signup history. A path can carry mail for people who never asked, and the report will not tap you on the shoulder. It will not hand you a rank, and it will not set a price. Ask who is on the list. Ask which domain sends. Ask what the refund line says when one network was sold as both, or when the list is not the list you named.

Price the object in your hand. The object is not a census and not a solo result. A solo is one letter to someone else's list. Read that difference before you argue about solo ad pricing. Pay for the letter only after the order names the list, the sending domain, and the refund line. An experience report is not the invoice, and it is not the audience.