koslib.com
Good, with 3 things to fix
koslib.com scored 76/100 (grade B). The main issues are DMARC policy applies to only 25% of mail and MTA-STS policy file is unreachable, plus 1 more.
Checked 2026-10-04 14:52 UTC
Strengthen the DMARC policy
Quarantines all mail that fails DMARC. Move on to reject once the reports stay clean.
_dmarc.koslib.com
Some DNS providers want just “_dmarc” here.
v=DMARC1; p=quarantine; rua=mailto:dmarc-7ab19fbfd312cfba016be98df1ca67da@mailvakt.com; adkim=r; aspf=r
v=DMARC1; p=quarantine; pct=25; rua=mailto:dmarc-7ab19fbfd312cfba016be98df1ca67da@mailvakt.com; adkim=r; aspf=r
How to apply it
- Sign in where your domain’s DNS is managed. This is often where you bought the domain, such as Cloudflare, GoDaddy or Namecheap.
- Find the existing TXT record with that name and replace its value.
- Save, then come back and re-check. DNS changes can take up to a few hours to show.
All checks
MXCan servers find your inbox?MX host is a CNAMENeeds attention
- Warning: MX host is a CNAME
RFC 2181 forbids an MX target that is an alias. Some senders refuse or delay delivery to mx01.mail.icloud.com, mx02.mail.icloud.com. Point the MX at the canonical hostname instead.
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 publishedPass
- Pass: DKIM key published
koslib.com publishes a DKIM key under sig1.
DMARCWhat happens to fakes?DMARC policy applies to only 25% of mailNeeds attention
- Warning: DMARC policy applies to only 25% of mail
pct=25 means the remaining 75% of failing mail is treated one step more leniently. Raise pct to 100 when you are confident.
How to fix this - 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?No issues foundPass
Nothing to report.
BIMICan inboxes show your logo?No BIMI recordInfo
- Info: No BIMI record
No BIMI record at default._bimi.koslib.com. BIMI is optional: it shows your logo next to your mail in supporting inboxes once DMARC is enforced.
How to fix this
MTA-STSIs mail to you encrypted?MTA-STS policy file is unreachableNeeds attention
- Warning: MTA-STS policy file is unreachable
https://mta-sts.koslib.com/.well-known/mta-sts.txt could not be fetched (HTTP 530). Senders cannot apply MTA-STS without the policy file, served over https with a valid certificate.
TLS-RPTWill you hear about failures?No TLS-RPT recordInfo
- Info: No TLS-RPT record
No TLS reporting record at _smtp._tls.koslib.com. TLS-RPT (RFC 8460) tells senders where to send daily reports about failed encrypted deliveries to you.
How to fix this
Other fixes
Set up a TLS report addressinstruction
Sending servers will report TLS failures when delivering to koslib.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.koslib.com
- Pick an address that will receive TLS reports: a mailbox you read (for example tls-reports@koslib.com, created first) or a TLS reporting service. 2. Publish a TXT record at _smtp._tls.koslib.com with the value v=TLSRPTv1; rua=mailto:<that address>.
Prepare BIMIinstruction
BIMI shows your logo next to messages in supporting inboxes, but only for mail that passes DMARC under an enforced policy.
Applies to: default._bimi.koslib.com
- Enforce DMARC first: p=quarantine or p=reject at 100% (no pct below 100). 2. Convert your logo to an SVG Tiny PS file and host it over HTTPS, for example https://koslib.com/bimi/logo.svg. 3. For Gmail and Apple Mail, obtain a VMC or CMC certificate for the logo. 4. Publish a TXT record at default._bimi.koslib.com with v=BIMI1, l= set to the logo URL and a= set to the certificate URL.