Two Woodpecker mailboxes on the same domain are not interchangeable test subjects. Compare them with the same rendered message and separate recipient observations before attributing a difference to the domain. Shared DNS does not establish that their actual signing, provider route, signatures or sending histories are identical.
Establish the comparison boundary
Choose two accounts you control and describe why they should be comparable. Record the mailbox provider, connection method, visible From address, signature and relevant tracking settings for each. If one account uses Google and another an SMTP relay, this is a comparison of two account routes as well as two senders.
Woodpecker documents choosing the sending mailbox for an individual test step. It also documents inbox rotation, where prospect assignments depend on account configuration and availability. For a diagnostic comparison, keep the sender assignment explicit so that rotation does not obscure which account produced which message.
Remove accidental content differences
Create a fixed, non-sensitive message fixture and review the final result for both accounts. The signature may contain different links, images or phone numbers even when the main body is identical. Decide whether signature differences are part of the real-world comparison or should be controlled in a second experiment.
Do not silently remove required sender or unsubscribe information. A stripped message might be useful as a separately labeled diagnostic variant, but cannot stand in for the normal campaign. Keep the initial test representative of the message recipients would actually receive.
Use two identifiable test runs
Create an LDM test for the first sender and another for the second, taking the current recipient list from each run. Submit original messages through the intended Woodpecker path. Keep the receiving-provider composition and observation schedule comparable. Do not assume the seed addresses are permanent, and do not leave them in a continuing outreach sequence.
If using Woodpecker's step-test interface, verify its chosen From mailbox before each send. The current editor documentation notes that a step test with multiple versions sends all versions, whereas a whole-campaign test can select versions randomly. Control or document those choices so that a sender comparison does not accidentally become a content comparison.
No campaign is executed by this guide. The procedure uses the sender's own permitted route and does not assume a native LDM integration.
Compare headers as well as folders
For each observed copy, record the receiving provider, folder, timestamp and message reference. Inspect available authentication results, including the actual DKIM signing domain and SPF identity. A shared visible domain does not prove that the two messages authenticated through the same identities.
If one copy fails authentication and another passes, investigate the account route and signing configuration before drawing conclusions about content. If both authenticate correctly but placement differs, the result remains an observation with several possible explanations, including mailbox history and recipient context. Authentication success is not an Inbox guarantee.
Avoid an aggregate that hides the question
A campaign total can conceal the sender-specific difference you intended to examine. Keep the two sets of results separate and state how many selected recipients were observed for each. Missing observations must remain separate from confirmed Spam; otherwise an account with a submission problem can appear to have a filtering problem.
A small panel cannot prove one employee's mailbox is permanently damaged or that changing the domain will solve the issue. Use the evidence to choose the next bounded check, such as signature parity or a route correction, and keep the original baseline for comparison.
Frequently asked questions
Can I test both accounts in one rotated campaign?
You can observe that campaign, but record the actual sender for every copy. Separate controlled runs are easier to interpret when the question concerns individual mailboxes.
Does the same domain mean the same DKIM result?
No. Inspect the received messages and their signing identities. Configuration and provider choices can differ between accounts.
Should I immediately replace the weaker account?
First establish whether it submitted correctly and whether the difference repeats under comparable conditions. One panel result is insufficient to explain the cause or predict all future mail.
Official references
Reviewed 2026-11-05; no measured sender ranking is asserted.