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๐Ÿ”’ SSL Certificate Monitor

The SSL monitor connects to your server, reads the full SSL/TLS certificate chain, and alerts you before your certificate expires.


๐ŸŽฏ Was Es Machtโ€‹

  • Connects to the host and reads the full certificate chain
  • Records issuer, subject, SANs (Subject Alternative Names), and fingerprint
  • Calculates days until expiry
  • Sends alerts at a configurable warning threshold (e.g., 30 days before expiry)
  • Stores certificate data in the Monitron database for historical tracking

โš™๏ธ Konfigurationโ€‹

EinstellungBeschreibungStandard
NameA friendly nameโ€”
HostDomain to checkโ€”
Warn Before Expiry (days)Alert this many days before expiry30

๐Ÿ“– Anwendungsbeispieleโ€‹

Example 1: Monitor your main domainโ€‹

EinstellungWert
Nameexample.com SSL
Addressexample.com
Warn Before Expiry30 days
Interval1 hour

Example 2: Monitor a wildcard certificateโ€‹

EinstellungWert
Name*.example.com SSL
Addressapp.example.com
Warn Before Expiry14 days

๐Ÿ“Š Was Aufgezeichnet Wirdโ€‹

DatenBeschreibung
IssuerWho issued the certificate (e.g., Let's Encrypt)
SubjectThe domain the certificate is issued for
SANsAll domains covered by the certificate
Valid FromCertificate start date
Valid UntilCertificate expiration date
Days Until ExpiryCalculated days remaining
FingerprintSHA-256 fingerprint
ChainFull certificate chain data

โš ๏ธ Alert Levelsโ€‹

BedingungStatus
Certificate valid, > 30 days remainingโœ… Up
Certificate valid, โ‰ค 30 days remainingโš ๏ธ Degraded (warning)
Certificate expiredโŒ Down
Connection failed / No certificateโŒ Down

๐Ÿ’ก Tippsโ€‹

  • Check frequency: SSL certificates don't change often. An hourly or every-6-hours interval is sufficient.
  • Let's Encrypt: If you use Let's Encrypt (90-day certificates), set the warning to 30 days. Certbot auto-renews at 30 days, so if you're still getting warnings at 14 days, renewal may be broken.
  • Multiple domains: Create separate SSL monitors for each domain, especially if they use different certificates.
  • View certificate details: Click on the monitor in the dashboard to see the full certificate information including the chain, SANs, and fingerprint.