­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ #!/bin/bash # Get the hostname and construct the domain HOSTNAME=$(hostname) DOMAIN="www${HOSTNAME}" PORT=2087 # Get certificate expiration date in epoch format EXPIRY_DATE=$(openssl s_client -connect ${DOMAIN}:${PORT} -servername ${DOMAIN} /dev/null | openssl x509 -noout -enddate | cut -d= -f2) EXPIRY_EPOCH=$(date -d "${EXPIRY_DATE}" +%s) CURRENT_EPOCH=$(date +%s) # Calculate days remaining DAYS_REMAINING=$(( (EXPIRY_EPOCH - CURRENT_EPOCH) / 86400 )) # Check expiration thresholds if [ "$DAYS_REMAINING" -le 14 ]; then echo "CRITICAL - SSL certificate for ${DOMAIN} expires in ${DAYS_REMAINING} days" exit 2 elif [ "$DAYS_REMAINING" -le 30 ]; then echo "WARNING - SSL certificate for ${DOMAIN} expires in ${DAYS_REMAINING} days" exit 1 else echo "OK - SSL certificate for ${DOMAIN} expires in ${DAYS_REMAINING} days" exit 0 fi