dns.uk.app
Kostenloses DNS-Tool

SSL-Zertifikat prüfen

Prüfen Sie das HTTPS-Zertifikat eines beliebigen Hosts: wann es abläuft, wer es ausgestellt hat, ob es den Namen abdeckt und ob die Kette vollständig ist.

What we check

Common fixes

“Unable to verify the first certificate” – serve the full chain (fullchain.pem), not just the leaf certificate. Host name mismatch – issue a certificate that includes this exact name, or a wildcard. Expired – check your ACME client’s renewal logs and any CAA-Einträge.

Frequently asked questions

Can I check a port other than 443?

Yes. Enter a port, for example 8443, or a mail port such as 465 or 993.

Can I check a server on my home network?

Only if it can be reached from the internet. For security we never connect to private or reserved IP addresses.

How can I get certificates for a home server?

Use the ACME DNS‑01 challenge. It works even when port 80 is closed. uk.app supports it out of the box – see the HTTPS guide.