Ask who signs the copy of the solo ad the list receives

Answer Forwarding and list software break SPF and DKIM when they change the path or the message. RFC 8617 defines the Authenticated Received Chain so later hops can see what earlier hops checked. On a solo ad, the practical question is who signs the copy the list actually receives.

The note that started this: RFC 8617, The Authenticated Received Chain (ARC) Protocol, RFC 8617.

A buyer imagines a straight line from the seller's button to the reader's inbox. The line usually has a platform in the middle, and sometimes a forward after that. Each of those hops can invalidate the check you asked about on August 4. The chain is how a careful receiver keeps a memory of the earlier check. It is not a substitute for knowing who signed this copy.

RFC 8617 is the ARC protocol. A forwarder that trusts the mail it received can seal a record of the authentication results it saw, then sign that seal. The next receiver can look at the seal if the original DKIM signature no longer checks, which is common when a list adds a footer or a forward changes the envelope. The seal is only as useful as the forwarder's reputation. A seal from a stranger does not launder a broken signature into a trusted brand. Ask who sealed, and ask who signed the body the reader will see.

What problem does ARC describe?

Forwarding and mailing lists often break SPF and DKIM, because the path or the message changes after the original signature. RFC 8617 defines a chain so a later receiver can see the earlier authentication results.

SPF checks the envelope against the sending IP. Forward the message and the IP is no longer the original sender's IP, so SPF fails. DKIM checks a hash of the signed fields. Add a tracking pixel, rewrite a link, or append a footer, and the hash fails. Lists do those things on purpose. A solo ad platform that rewrites every link for its own click count is doing the thing that breaks the signature, unless it signs the rewritten copy with a domain you were told about.

That is the desk version of a specification that reads like plumbing. If you buy solo ads, you are buying a copy that may not be the copy that was originally signed. The click tracker, the footer, the from-name swap the buyer requested: each one can be the edit that makes the old signature false. The order should say who signs after the edit.

• The seller names the system that rewrites links.
• The seller names the domain that signs after the rewrite.
• A live header shows that d= value.
• An ARC seal, if they mention one, is tied to a named forwarder.

Does an ARC chain mean the solo ad is authenticated as the brand?

No. ARC records what earlier hops claimed to have checked. The domain that signs the copy the list actually receives is still the domain you should ask the seller to name.

A chain can say an earlier hop saw a pass for a domain, and the current hop sees a fail because the body changed. The receiver then decides whether it trusts the sealer enough to accept the earlier pass. You cannot make that decision for Gmail. You can refuse to be surprised. If the brand domain is not the signer of the final copy, say that in the quote in one sentence. The reader may see a via line. A DMARC policy on the brand domain may treat the mail as unaligned. Both outcomes are ordinary. Hiding them until after the charge is how orders become complaints.

If you sell the send, sign the version you transmit. Do not describe yesterday's signature as if it survived the click wrapper. The wrapper is your product. The signature has to match the product. A buyer who asks who signs is asking about the mail their offer will ride, not about a diagram in a help center.

What should you ask when a platform stands between the sender and the list?

Ask who signs the message after any rewrite, and ask for the d= domain on a live copy. A platform that changes the body or the from-address and does not sign again has broken the check the next mailbox wanted.

Put the answer on the same line as the from-name. If they use a chain and can explain it, good. If they cannot say whether a rewrite happens, assume it happens, because click tracking is the business. Then require the signer of the rewritten copy.

The rest of the quote still lives on safe solo ads sellers. The chain is one more fact, not a new religion. Someone signs the copy the list receives. Name them before the money moves.