Free tool SSL check.
SSL check.
What it covers, and when it dies.
Issuer, expiry, the names on it, the chain and the TLS version actually negotiated. It'll talk to a host with a broken certificate too — that's the case you needed a checker for.
Try , , .
More free tools
What is my IP
Your address, its reverse DNS, and who announces the range it sits in.
WHOIS lookup
Who holds a domain, an IP range or an AS number, and until when.
DNS lookup
Every record for a domain — A, MX, TXT, NS, CAA — in one answer.
Email deliverability
SPF, DKIM and DMARC, with the gaps that put your mail in spam.
Subnet calculator
CIDR to range, mask, host count and the split into smaller blocks.