OpenSSL Tips
Check the expiration date of an SMTP Server SSL certificate
1 min readApr 23, 2020
$ printf ‘quit\n’ | openssl s_client -connect SMTPSERVERIP:25 -starttls smtp | openssl x509 -enddate -nooutdepth=0 OU = Domain Control Validated, OU = X Standard Wildcard SSL, CN = *.mydomain.com
verify return:1
250 SIZE 0
DONE
notAfter=Sep 15 23:59:59 2019 GMT
Get SSL cert of an FTP server to use in ftp application code
openssl s_client -connect ftp.mydomain.com:21 -starttls ftp
---
..
Server certificate
-----BEGIN CERTIFICATE-----
MIIGMjCCBRqgAwIBAgIQDi8HsYslojF4Puj7rOpG9TANBgkqhkiG9w0BAQsFADBe
MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3
d3cuZGlnaWNlcnQuY29tMR0wGwYDVQQDExRSYXBpZFNTTCBSU0EgQ0EgMjAxODAe
Fw0xOTAyMTQw
