A script to return the number of days before a SSL certificate expires. Visit https://sbcode.net/zabbix/system-run/ for instructions

checkssl.sh

data=`echo | openssl s_client -servername $1 -connect $1:443 2>/dev/null | openssl x509 -noout -enddate | sed -e 's#notAfter=##'`

ssldate=`date -d "${data}" '+%s'`
nowdate=`date '+%s'`
diff="$((${ssldate}-${nowdate}))"

echo $((${diff}/86400))

We added support for a second parameter "PORT".
By default without specifying a port is uses 443.
If you use a key: checkssl.sh[costlogic.adm.swri.edu,7002]
It will test using port 7002.

Looks like it works all around.. If you see any issues it can be reverted by removing the IF statement and replacing $PORT with 443.

[root@zabbix-svr ~]# cat /usr/share/zabbix/externalscripts/checkssl.sh
#!/bin/bash
if [ -z $2 ] ; then
PORT=443
else
PORT=$2
fi
data=echo | openssl s_client -servername $1 -connect $1:$PORT 2>/dev/null | openssl x509 -noout -enddate | sed -e 's#notAfter=##'

ssldate=date -d "${data}" '+%s'
nowdate=date '+%s'
diff="$((${ssldate}-${nowdate}))"

echo $((${diff}/86400))

This could be something you want to include in your script for future use. It may not be as clean but it works.

Thanks

missing or " " on data, ssldate & nowdate.

Thanks, works like a charm.
Particularly useful if we have some protected hosts and public check of SSL expiration is not possible. Script is doing it locally on own host, nice.
All the best