Excellent, with 1 thing to fix

dropbox.com scored 92/100 (grade A). The main issue is SPF record is very long. Detected senders: Google Workspace, Amazon SES and Zendesk.

Checked 2026-10-04 02:03 UTC · fresh check

5 passed1 needs attention0 failing2 for informationDetected senders: Google Workspace, Amazon SES, Zendesk

All checks

MXCan servers find your inbox?No issues foundPass

Nothing to report.

SPFWho may send as you?SPF record is very longNeeds attention

Warning: SPF record is very long
The SPF record is 562 characters. Long TXT answers can exceed the 512-byte UDP limit and force fallback to TCP, which some receivers do not do. Replace individual IP ranges with includes or ranges, or remove services you no longer use. (Only the total length is checked: the resolver returns the record already joined, so the 255-character limit on each individual string cannot be seen here.)
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 publishedPass

Pass: DKIM key published
dropbox.com publishes a DKIM key under zendesk1, zendesk2.

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.dropbox.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.dropbox.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

Publish the MTA-STS recordTXT

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

TypeTXT

Name / Host

_mta-sts.dropbox.com

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

Value

v=STSv1; id=202610040203

Host the MTA-STS policy filepolicy-file

Serve this file over HTTPS with a valid certificate for mta-sts.dropbox.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.dropbox.com/.well-known/mta-sts.txt

Contents

version: STSv1
mode: testing
mx: mxa-001ed902.gslb.pphosted.com
mx: mxb-001ed902.gslb.pphosted.com
max_age: 604800

Set up a TLS report addressinstruction

Sending servers will report TLS failures when delivering to dropbox.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.dropbox.com

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