Some sequencers and deliverability checkers will flag PTR or reverse DNS (rDNS) as "failing" or "missing" for the servers your mailboxes send from. If you've seen this warning, you don't need to take any action — it does not mean your setup is broken, and it does not hurt your inbox placement.
Why this happens
We don't publish PTR (reverse DNS) records for our sending IPs — this is a deliberate part of how our sending infrastructure is built, not an oversight. On top of that, our sending IP addresses rotate frequently as part of how we manage sender reputation, so the specific IP behind any one of your mailboxes changes often rather than staying fixed — see One of my sending IPs shows as blacklisted for the same pattern with blacklist checkers. Because a checker tool inspects a single IP at a single moment, and that IP may already have rotated again by the time you look it up, it will reliably report a PTR "fail" or "missing" — that's expected given how the infrastructure works, not a sign that anything is broken.
Additionally, users cannot configure PTR records or custom DNS settings themselves. This is a deliberate choice to maintain the integrity and efficiency of Maildoso's centrally managed email delivery system.
If you're also being asked (for example by a deliverability audit) about List-Unsubscribe headers, the same "managed, not configurable" answer applies — see Does Maildoso support List-Unsubscribe (one-click unsubscribe) headers? in this collection.
What actually matters for deliverability
SPF, DKIM, and DMARC — these authentication records are what inbox providers check, and we manage them for your Maildoso domains automatically. If a checker still reports them missing, see My DKIM or DMARC isn't detected by a third-party checker.
Sending reputation and engagement — consistent warmup (see How warmup works and how to start it) and sensible daily volume matter far more than a static reverse DNS entry.
For modern cold email, a fixed PTR/rDNS record is not required for inbox placement.
Maildoso's internal testing has confirmed that PTR records are not a critical factor for inbox placement, further supporting the focus on SPF, DKIM, and DMARC for deliverability.
What you should do
You can safely ignore a standalone PTR/rDNS warning from a third-party checker.
Keep your warmup running and your sending volumes reasonable.
Make sure your authentication (SPF, DKIM, DMARC) is passing — for Maildoso-managed domains it already is.
If you're seeing an actual deliverability problem — messages landing in spam, unexpected bounces, or a drop in replies — contact us and we'll review your specific case rather than relying on a single automated check.