cox.net: mail servers, SPF, DMARC, DKIM and reputation

Mail servers for cox.net

DNS lists 3 mail hosts for cox.net, starting with mta7.am0.yahoodns.net. Lower priority values are tried first; the rest exist for failover.

Who runs the mail

The hosts match the pattern of Yahoo Mail. Yahoo's servers (shared by Yahoo Mail and AOL) are conservative with handshake replies and often defer or greylist probes, so a mailbox check can come back unverified even for a real inbox. Spaw re-checks those addresses when you pass a callback.

What this means for verification

For cox.net, verification runs the whole pipeline: syntax, live MX, the open lists, and then the SMTP handshake with the mail host, with no message ever transmitted. Each verdict carries a machine-readable reason.

SPF for cox.net

cox.net publishes an SPF record; it authorises 2 included sender lists, and the record ends in ?all (neutral): unlisted servers are neither authorised nor refused, which gives receivers little to act on.

DMARC for cox.net

cox.net has DMARC in monitoring mode (p=none). Receivers report what they see but deliver failing mail anyway, so the record protects nothing yet.

Why it matters

Receivers use SPF, DKIM, and DMARC together to decide whether a message really came from cox.net. A domain with a strict SPF record and an enforcing DMARC policy is hard to spoof and easier to deliver for; one without either is neither. Spaw reports has_spf and dmarc_policy on every lookup and adds a small risk weight when SPF is missing.

DKIM keys for cox.net

cox.net publishes no DKIM key under any of the common selectors this checker knows. Read that narrowly: DKIM selectors are free-form labels, so a domain signing under its own private selector name passes this check unseen. The selector on a real message's DKIM-Signature header is the only definitive answer.

What the check reads

DKIM keys live in DNS at <selector>._domainkey.cox.net, one TXT record per selector, and the selector is chosen by whoever signs the mail. This checker asks for the selectors the large providers and sending platforms use by default (google, selector1 and selector2 for Microsoft 365, k1, s1, fm1 and about thirty more), so a key found here is a real key, and a key not found here may simply sit under a name the list does not know.

How it fits with SPF and DMARC

cox.net has DMARC in monitoring mode (p=none). Receivers report what they see but deliver failing mail anyway, so the record protects nothing yet. cox.net publishes an SPF record; it authorises 2 included sender lists, and the record ends in ?all (neutral): unlisted servers are neither authorised nor refused, which gives receivers little to act on.

Transport security for cox.net

cox.net publishes no an MTA-STS policy record record at _mta-sts.cox.net. Without MTA-STS, a sender that cannot negotiate TLS with the mail host may fall back to delivering in the clear, and an attacker on the path can force exactly that. cox.net publishes no a TLS-RPT record record at _smtp._tls.cox.net. TLS-RPT would give the domain owner a daily report of delivery attempts that could not establish TLS; without it, failures are invisible.

Brand indicators for cox.net

cox.net publishes no a BIMI record record at default._bimi.cox.net. BIMI is optional and mostly cosmetic; it only becomes possible once DMARC enforces quarantine or reject.

SPF details for cox.net

cox.net publishes SPF. The policy's all qualifier is ?all (neutral: unlisted servers are neither authorised nor refused). Evaluating it takes 5 DNS lookups, within the ten RFC 7208 allows.

DMARC details for cox.net

cox.net has DMARC in monitoring mode (p=none). Receivers report what they see but deliver failing mail anyway, so the record protects nothing yet. The policy applies to all of the domain's mail (pct=100). Aggregate reports are collected (rua= is set), so the owner sees who sends as the domain.

Is cox.net disposable?

cox.net is a consumer email service rather than a company domain: real people, personal accounts, and no way to infer an employer from the address.

About the domain

Its mail is handled by Yahoo Mail.

How Spaw treats addresses at cox.net

For cox.net, verification runs the whole pipeline: syntax, live MX, the open lists, and then the SMTP handshake with the mail host, with no message ever transmitted. Each verdict carries a machine-readable reason.

Common questions about cox.net

Does cox.net accept mail?

cox.net accepts mail through yahoo's mail servers.

Does cox.net publish SPF and DMARC?

cox.net publishes SPF ending in ?all and a DMARC policy of none.

Is cox.net a disposable, relay or free-provider domain?

cox.net is a free mailbox provider, so an address there is a consumer inbox rather than a company's.

Does cox.net publish DKIM, MTA-STS, TLS-RPT or BIMI?

cox.net does not publish MTA-STS, does not publish TLS-RPT and does not publish BIMI. None of the common DKIM selectors publishes a key, which does not mean the domain signs nothing: a selector outside the common list is invisible to this check.

Where does this report come from?

Live DNS, the open disposable, role and free-provider lists, the registry's RDAP record and the threat blocklists the IP product installs, read on 2026-10-15 and cached for a week. Nothing here says anything about a person; it describes the domain's mail setup on that day.

Check another domain

• Email checker
• MX record lookup
• SPF & DMARC checker
• Disposable email domain checker
• DKIM checker
• MTA-STS, TLS-RPT and BIMI checker
• The same answer over the API: GET /api/v1/email/domain/cox.net