Written by James McDonald

September 12, 2019

Method 1 – openssl

printf 'quit\n' | openssl s_client -connect $SERVERNAME:25 -starttls smtp | openssl x509 -enddate -noout

Method 2 – Google Chrome

Run Google Chrome and bypass the ERR_UNSAFE_PORT error by specifying the --explicitly-allowed-ports=465 option on the command line. The following command is for MacOS

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --explicitly-allowed-ports=465

Open the link to the SSL port of the email server. i.e https://mail.example.com:465 And you get a nice GUI displaying the trust chain and expiry date.



Submit a Comment

Your email address will not be published. Required fields are marked *

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

The reCAPTCHA verification period has expired. Please reload the page.

You May Also Like…

Meraki Open Source Licenses

Until today I assumed that Meraki was built in-house with only closed source software. But having a look at the...


If you have Veeam backup failing with the Updating BCD failed with Cannot update SafeBoot flag and SentinelOne is...