linkedin.com
The three core checks pass. What is missing is the transport and trust layer around them.
6 of 8 checks pass · 2 tools visible in DNS · nothing urgent
1 · Authentication and transport
SPF
PassValid, soft failAnything not on the list is accepted but marked. Google recommends ~all; with DMARC enforced it is as strong as -all.
v=spf1 ip4:199.101.162.0/25 ip4:108.174.3.0/24 ip4:108.174.6.0/24 ip4:108.174.0.0/24 ip6:2620:109:c00d:104::/64 ip6:2620:109:c006:104::/64 ip6:2620:109:c003:104::/64 ip6:2620:119:50c0:207::/64 ip4:199.101.161.130 mx mx:docusign.net ~all
DKIM
Pass1 key foundSelectors google publish a public key.
google._domainkey
DMARC
PassEnforced (p=reject)Failing mail is rejected. This is the finish line.
v=DMARC1; p=reject; rua=mailto:d@rua.agari.com,mailto:yfy3q-9359@rua.dmarc.emailanalyst.com; ruf=mailto:d@ruf.agari.com
MX
Pass4 hostsMore than one receiving server, so a single outage does not bounce mail.
10 mail-a.linkedin.com 20 mail-c.linkedin.com 30 mail-d.linkedin.com 40 mail.linkedin.com
MTA-STS
ReviewNot publishedSending servers cannot tell that this domain requires TLS, so inbound mail can be downgraded to plain text by anyone on the path.
TLS-RPT
PassPublishedTLS failure reports have somewhere to go.
v=TLSRPTv1; rua=mailto:tlsreports@linkedin.com
BIMI
PassPublishedLogo record found and DMARC qualifies. Yahoo shows it from the record; Gmail and Apple Mail also need a VMC or CMC certificate (the a= tag).
v=BIMI1; l=https://media.licdn.com/media/AAYQAQQhAAgAAQAAAAAAABrLiVuNIZ3fRKGlFSn4hGZubg.svg; a=https://media.licdn.com/media/AAYABAQhAAgAAQAAAAAAAYFI0DP_wvHFSv6mYduMZuEwSA.pem;
DNSSEC
OptionalNot signedOptional. Signing the zone protects every record in this report from tampering.
2 · Tools visible in DNS
| Layer | Tool | Evidence |
|---|---|---|
| Mailbox | Google Workspace | DKIM google._domainkey |
| DMARC reporting | Agari | DMARC rua=mailto:…@rua.agari.com |
Only tools that leave a DNS trace appear. A shared DKIM selector is attributed only when its CNAME target names the vendor.
3 · Sender requirements (Google, Yahoo, Microsoft)
| Requirement | Applies to | Status | Note |
|---|---|---|---|
| Authenticate with SPF or DKIM | GoogleYahooMicrosoft | Verified | At least one method is in place. |
| Bulk senders: both SPF and DKIM | GoogleYahoo | Verified | Both are present. |
| Publish a DMARC record (p=none is enough) | GoogleYahooMicrosoft | Verified | Policy is p=reject. |
| From: domain aligns with SPF or DKIM | GoogleYahooMicrosoft | Not checkable here | Needs a real message. The Send-a-Test report will check this. |
| Valid forward and reverse DNS for sending IPs | GoogleYahoo | Not checkable here | Depends on the sending server, not the domain. |
| Encrypt in transit (TLS) | GoogleYahoo | Not checkable here | Outbound TLS depends on your sending tool; MTA-STS would cover inbound. |
| One-click unsubscribe (RFC 8058) for marketing mail | GoogleYahoo | Not checkable here | A message header, not a DNS record. Microsoft recommends it rather than requiring it. |
| Spam complaint rate under 0.1% (0.3% is the hard limit) | GoogleYahoo | Not checkable here | Read it in Google Postmaster Tools and Yahoo Sender Hub. Google’s target is 0.1%; 0.3% is where enforcement starts. |
4 · What to fix, in order
-
P3
Publish MTA-STS (record and policy file)
Tells sending servers to require TLS to your MX hosts, which prevents downgrade attacks. The TXT record alone does nothing: the policy file must be served over HTTPS at mta-sts.linkedin.com. Start in testing mode, watch TLS-RPT, then switch to enforce.
Publish at_mta-sts.linkedin.com and https://mta-sts.linkedin.com/.well-known/mta-sts.txtTXT v=STSv1; id=2026100401 mta-sts.txt: version: STSv1 mode: testing mx: mail-a.linkedin.com mx: mail-c.linkedin.com mx: mail-d.linkedin.com mx: mail.linkedin.com max_age: 86400
-
P3
Sign the zone with DNSSEC
Protects every record in this report from being swapped in transit. Two steps: enable signing at your DNS host (one switch at Cloudflare and most others), then add the DS record it gives you at your registrar.
Publish atlinkedin.com
Appendix · Raw DNS answers
| Name | Type | Answer |
|---|---|---|
| linkedin.com | MX | 10 mail-a.linkedin.com 20 mail-c.linkedin.com 30 mail-d.linkedin.com 40 mail.linkedin.com |
| linkedin.com | A | 130.211.32.14 |
| linkedin.com | TXT | v=spf1 ip4:199.101.162.0/25 ip4:108.174.3.0/24 ip4:108.174.6.0/24 ip4:108.174.0.0/24 ip6:2620:109:c00d:104::/64 ip6:2620:109:c006:104::/64 ip6:2620:109:c003:104::/64 ip6:2620:119:50c0:207::/64 ip4:199.101.161.130 mx mx:docusign.net ~all (+ 23 other TXT records: site-verification tokens and the like, omitted) |
| _dmarc.linkedin.com | TXT | v=DMARC1; p=reject; rua=mailto:d@rua.agari.com,mailto:yfy3q-9359@rua.dmarc.emailanalyst.com; ruf=mailto:d@ruf.agari.com |
| <selector>._domainkey.linkedin.com | TXT | google → key published |
| _mta-sts.linkedin.com | TXT | no record |
| _smtp._tls.linkedin.com | TXT | v=TLSRPTv1; rua=mailto:tlsreports@linkedin.com |
| default._bimi.linkedin.com | TXT | v=BIMI1; l=https://media.licdn.com/media/AAYQAQQhAAgAAQAAAAAAABrLiVuNIZ3fRKGlFSn4hGZubg.svg; a=https://media.licdn.com/media/AAYABAQhAAgAAQAAAAAAAYFI0DP_wvHFSv6mYduMZuEwSA.pem; |