digicert.com

digicert.com · Last checked 2026-10-04 02:02 UTC

digicert.com

Excellent, with 1 thing to fix

digicert.com scored 92/100 (grade A). The main issue is DKIM key shorter than 2048 bits. Detected senders: Microsoft 365.

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

1 passed1 needs attention0 failing6 for informationDetected senders: Microsoft 365

All checks

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

    All mail for digicert.com goes to digicert-com.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?DKIM key shorter than 2048 bitsNeeds attention
  • Warning: DKIM key shorter than 2048 bits

    selector2 (1024-bit), mail (1024-bit) uses an RSA key below 2048 bits. Short keys can be factored and some receivers treat them as weak. Rotate to a 2048-bit key at your sending provider.

  • Pass: DKIM key published

    digicert.com publishes a DKIM key under selector1, selector2, s1, s2, mail.

DMARCWhat happens to fakes?DMARC policy is quarantine; consider rejectInfo
  • Info: DMARC policy is quarantine; consider reject

    Failing mail goes to spam rather than being refused. When reports show no legitimate failures, reject gives the strongest protection.

    How to fix this
AlignmentDoes it match your From?SPF alignment depends on a custom Return-PathInfo
  • Info: SPF alignment depends on a custom Return-Path

    This is a heuristic. Your SPF record only authorizes third-party senders (mktomail.com). By default they bounce from their own Return-Path domain, and SPF then passes for that domain, not digicert.com. Even relaxed alignment needs the Return-Path's organizational domain to be digicert.com, so set up a custom Return-Path (bounce) domain under digicert.com with each provider, and sign with DKIM as digicert.com.

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.digicert.com. 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.digicert.com. 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

Strengthen the DMARC policyTXT

Rejects mail that fails DMARC, the strongest protection against spoofing.

TypeTXT
Name / Host
_dmarc.digicert.com

Some DNS providers want just “_dmarc” here.

Value
v=DMARC1; p=reject; rua=mailto:dmarc_agg@vali.email,mailto:dmarc@digicert.com; adkim=r; aspf=r
Replaces
v=DMARC1; p=quarantine; rua=mailto:dmarc_agg@vali.email,mailto:dmarc@digicert.com

Publish the MTA-STS recordTXT

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

TypeTXT
Name / Host
_mta-sts.digicert.com

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

Value
v=STSv1; id=202610040202

Host the MTA-STS policy filepolicy-file

Serve this file over HTTPS with a valid certificate for mta-sts.digicert.com. 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.digicert.com/.well-known/mta-sts.txt
Contents
version: STSv1
mode: testing
mx: digicert-com.mail.protection.outlook.com
max_age: 604800

Set up a TLS report addressinstruction

Sending servers will report TLS failures when delivering to digicert.com, 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.digicert.com

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