Sometimes we need to check the certificate issuance date. Nmap and curl are a very good tool for this.
Both of these tools allow for advanced analysis of the SSL connection. Let’s try to check the certificate date with nmap:

$ nmap -p 443 --script ssl-cert soban.pl

To be more precise, let’s leave the date and time alone:

$ nmap -p 443 --script ssl-cert soban.pl | grep after | awk '{ print $5 }'

Here is the result:

In my experience nmap is a very good tool – however curl is much faster, to use it, do the following:

$ curl -X GET -i 'https://google.com' | grep -i 'date:' | grep GMT

This is the effect:

It is worth getting acquainted with both tools. Besides checking the date of the certificate, they offer a number of other possibilities.

Artykuł Checking SSL certyfikat date using nmap and curl pochodzi z serwisu soban.