DMARC p=quarantine vs p=reject: which one is right for cold email
Reject sounds stronger. Quarantine ships safer. Here is the operator-grade reasoning for picking the right policy.
Rejwan Nirob·Apr 7, 2026·6 min readDMARC has three policies - none, quarantine, reject. Most senior security guides will tell you to push to reject as fast as possible. Most cold-email operators ignore that advice. Both groups are right, in their own context.
What the policies actually do
p=none means observe and report. The receiving server applies normal spam filtering and emails the DMARC reports to you. Nothing is blocked.
p=quarantine means the receiving server should treat unaligned mail as suspicious - usually routed to spam. Email still reaches the recipient, but in a folder they may never check.
p=reject means the receiving server bounces unaligned mail at the SMTP layer. The recipient never sees it.
Why cold email defaults to quarantine
A new domain on day one of warmup will sometimes mis-align - a forwarding chain, a CRM auto-reply, a sender pointing at a slightly different envelope address. With p=reject those messages bounce hard, and a chain of bounces is a deliverability signal you do not want during warmup.
Quarantine logs the failure, sends you the report, and lets the message through with a spam-bias. Once you have 14 days of clean reports, the move to reject is safe.
The Inboxlee default
- Day 1 to day 14 - p=quarantine, percentage 100
- Day 14+ - recommended move to p=reject after a clean DMARC report week
- aspf and adkim defaults to relaxed alignment for compatibility
- rua reports route to your workspace inbox automatically
Domains that start at p=reject during the first warmup week tend to accumulate noticeably more soft-bounce noise than domains that start at quarantine. Soft bounces hurt sender reputation. The phased approach prevents that, which is why we default to quarantine for the first two weeks and recommend the move to reject only after a clean DMARC report week.
See how Inboxlee handles DMARCFrequently asked
Should I use p=none, p=quarantine, or p=reject for cold email?
Start at p=quarantine. p=none gives reporting but no enforcement and providers treat it as soft. p=reject can silently bounce legitimate mail during the first 14 days when DMARC alignment is still settling. Quarantine is the safe default and what Inboxlee ships on day one.
When should I move from p=quarantine to p=reject?
After roughly 14 days of clean DMARC reports - no alignment failures, no unexpected soft bounces, no third-party senders missing alignment. Moving too early during warmup can drop legitimate mail; moving too late leaves you marginally more exposed to spoofing.
Does Gmail or Microsoft punish me for staying at p=quarantine forever?
No. Gmail and Microsoft require any DMARC policy (none, quarantine, or reject) for senders above 5,000 emails per day, but they do not penalize you for choosing quarantine over reject. The choice is yours; quarantine is the operator-safe default.
What is DMARC alignment - aspf and adkim?
Alignment means the visible From domain matches (or is a subdomain of) the SPF-authorized envelope sender (aspf) and the DKIM-signing domain (adkim). Relaxed alignment allows subdomains; strict requires an exact match. Relaxed is the safe default for cold email - what Inboxlee provisions automatically.