A simple program to print certificate information.
The x509 tool is takes only a hostname / url as an argument
and will make a dial that hostname with tls.Dial
e % ./x509 ejj.io
{
"IsCA": false,
"Version": 3,
"SerialNumber": 15054454955724096237524256656952086492,
"Issuer": "USCloudflare, Inc. Cloudflare Inc ECC CA-3",
"Subject": "USCloudflare, Inc. ejj.io",
"NotBefore": "2022-05-02T00:00:00Z",
"NotAfter": "2023-05-02T23:59:59Z",
"KeyUsage": 1,
"DNSNames": [
"ejj.io",
"*.ejj.io"
],
"EmailAddresses": null,
"IPAddresses": null,
"URIs": null,
"PermittedDNSDomainsCritical": false,
"PermittedDNSDomains": null,
"ExcludedDNSDomains": null,
"PermittedIPRanges": null,
"ExcludedIPRanges": null,
"PermittedEmailAddresses": null,
"ExcludedEmailAddresses": null,
"PermittedURIDomains": null,
"ExcludedURIDomains": null
}