rakuten.co.jp

rakuten.co.jp · Last checked 2026-10-04 02:12 UTC

rakuten.co.jp

Good, with 1 thing to fix

rakuten.co.jp scored 88/100 (grade B). The main issue is no DKIM key found for the common selectors. Detected senders: Microsoft 365.

Checked 2026-10-04 02:12 UTC · fresh check

3 passed1 needs attention0 failing4 for informationDetected senders: Microsoft 365

All checks

MXCan servers find your inbox?Only one MX hostInfo
  • Info: Only one MX host

    All mail for rakuten.co.jp goes to rakuten-co-jp.mail.protection.outlook.com. Most hosted providers make that one name highly available; if you run your own server, consider a backup MX.

SPFWho may send as you?SPF ends in softfail (~all)Info
  • Info: SPF ends in softfail (~all)

    "~all" is common and works well with DMARC. "-all" is stricter; switch when you are sure every sender is listed.

DKIMAre your emails signed?No DKIM key found for the common selectorsNeeds attention
  • Warning: No DKIM key found for the common selectors

    None of the 47 selectors probed under rakuten.co.jp publish a DKIM key. DNS cannot list selectors, so a key under a custom selector may exist: find the s= value in the DKIM-Signature header of a message you sent and check that selector. If DKIM is not set up, enable it at each service that sends mail for rakuten.co.jp.

DMARCWhat happens to fakes?No issues foundPass

Nothing to report.

AlignmentDoes it match your From?No issues foundPass

Nothing to report.

BIMICan inboxes show your logo?No issues foundPass

Nothing to report.

MTA-STSIs mail to you encrypted?No MTA-STS recordInfo
  • Info: No MTA-STS record

    No MTA-STS record at _mta-sts.rakuten.co.jp. MTA-STS (RFC 8461) makes sending servers require TLS and a valid certificate when delivering to you, which blocks downgrade attacks.

    How to fix this
TLS-RPTWill you hear about failures?No TLS-RPT recordInfo
  • Info: No TLS-RPT record

    No TLS reporting record at _smtp._tls.rakuten.co.jp. TLS-RPT (RFC 8460) tells senders where to send daily reports about failed encrypted deliveries to you.

    How to fix this

How to fix it

Enable DKIM for Microsoft 365instruction

Microsoft 365 generates the DKIM key for each account, so the exact record must come from Microsoft 365. Without DKIM, mail it sends for rakuten.co.jp cannot pass DMARC through DKIM.

Applies to: selector1._domainkey.rakuten.co.jp

  1. In Microsoft 365, enable DKIM signing for rakuten.co.jp: tenant-specific: copy Selector1CNAME/Selector2CNAME from Microsoft 365 Defender > Email authentication > DKIM. Publish exactly the record Microsoft 365 shows (TXT or CNAME) at the host name it gives, then turn signing on. Instructions: https://learn.microsoft.com/microsoft-365/security/office-365-security/email-authentication-dkim-configure

Enable DKIM for Microsoft 365instruction

Microsoft 365 generates the DKIM key for each account, so the exact record must come from Microsoft 365. Without DKIM, mail it sends for rakuten.co.jp cannot pass DMARC through DKIM.

Applies to: selector2._domainkey.rakuten.co.jp

  1. In Microsoft 365, enable DKIM signing for rakuten.co.jp: tenant-specific: copy Selector1CNAME/Selector2CNAME from Microsoft 365 Defender > Email authentication > DKIM. Publish exactly the record Microsoft 365 shows (TXT or CNAME) at the host name it gives, then turn signing on. Instructions: https://learn.microsoft.com/microsoft-365/security/office-365-security/email-authentication-dkim-configure

Publish the MTA-STS recordTXT

Tells sending servers that rakuten.co.jp publishes an MTA-STS policy at https://mta-sts.rakuten.co.jp/.well-known/mta-sts.txt. Change the id whenever the policy file changes.

TypeTXT
Name / Host
_mta-sts.rakuten.co.jp

Some DNS providers want just “_mta-sts” here.

Value
v=STSv1; id=202610040212

Host the MTA-STS policy filepolicy-file

Serve this file over HTTPS with a valid certificate for mta-sts.rakuten.co.jp. It lists your MX hosts and starts in testing mode; switch to mode: enforce once TLS-RPT reports show no failures.

Location
https://mta-sts.rakuten.co.jp/.well-known/mta-sts.txt
Contents
version: STSv1
mode: testing
mx: rakuten-co-jp.mail.protection.outlook.com
max_age: 604800

Set up a TLS report addressinstruction

Sending servers will report TLS failures when delivering to rakuten.co.jp, which you need before enforcing MTA-STS. The address must accept TLS reports; a DMARC report address does not necessarily do so.

Applies to: _smtp._tls.rakuten.co.jp

  1. Pick an address that will receive TLS reports: a mailbox you read (for example tls-reports@rakuten.co.jp, created first) or a TLS reporting service. 2. Publish a TXT record at _smtp._tls.rakuten.co.jp with the value v=TLSRPTv1; rua=mailto:<that address>.