https://www.claudiokuenzler.com Yet another tech blog made in Switzerland en-en https://www.claudiokuenzler.com/graph/lay/pelican-header.jpg https://www.claudiokuenzler.com https://www.claudiokuenzler.com/blog/1537/regression-fix-check-smart-monitoring-plugin https://www.claudiokuenzler.com/blog/1537/regression-fix-check-smart-monitoring-plugin A regression was introduced in check_smart 6.18.1, which is now fixed. Sat, 09 May 2026 08:34:34 +0000 https://www.claudiokuenzler.com/blog/1535/check-smart-6.18.1-security-fix-vulnerability https://www.claudiokuenzler.com/blog/1535/check-smart-6.18.1-security-fix-vulnerability A command injection vulnerability was fixed in this security release 6.18.1. Fri, 24 Apr 2026 13:22:21 +0000 https://www.claudiokuenzler.com/blog/1533/powerdns-monitoring-security-release https://www.claudiokuenzler.com/blog/1533/powerdns-monitoring-security-release The check_powerdns_auth monitoring plugin not only checks PowerDNS and its statistics, but also alerts if a security release is available! Wed, 22 Apr 2026 18:56:06 +0000 https://www.claudiokuenzler.com/blog/1532/check-smart-6.18.0-sudo-command-path-fix-nvme-io-error https://www.claudiokuenzler.com/blog/1532/check-smart-6.18.0-sudo-command-path-fix-nvme-io-error The newest release, 6.18.0, fixes an execution bug in FreeBSD and adds NVME i/o error detection. Tue, 21 Apr 2026 12:45:37 +0000 https://www.claudiokuenzler.com/blog/1531/monitoring-rabbitmq-queues-handle-no-queue-situation https://www.claudiokuenzler.com/blog/1531/monitoring-rabbitmq-queues-handle-no-queue-situation Improved the monitoring plugin check_rabbitmq_queue to handle RabbitMQ without any queues. Wed, 15 Apr 2026 13:49:50 +0000 https://www.claudiokuenzler.com/blog/1530/mysql-upgrade-unknown-variable-max-allowed-packet-znuny-config https://www.claudiokuenzler.com/blog/1530/mysql-upgrade-unknown-variable-max-allowed-packet-znuny-config After a Debian Linux server and its MariaDB was upgraded, mysqldump ran into warnings and mysql_upgrade would not work anymore. Wed, 08 Apr 2026 12:52:58 +0000 https://www.claudiokuenzler.com/blog/1529/znuny-internal-server-error-after-debian-upgrade https://www.claudiokuenzler.com/blog/1529/znuny-internal-server-error-after-debian-upgrade After Debian was upgraded to Trixie, the Znuny Open Source Ticket System stopped working. Sat, 04 Apr 2026 07:01:26 +0000 https://www.claudiokuenzler.com/blog/1527/magento-adobe-commerce-attacked-polyshell-sessionreaper-exploit-vulnerability https://www.claudiokuenzler.com/blog/1527/magento-adobe-commerce-attacked-polyshell-sessionreaper-exploit-vulnerability Attacks on Magento (Adobe Commerce) against the SessionReaper and PolyShell vulnerabilities are on the rise. Thu, 26 Mar 2026 06:33:22 +0000 https://www.claudiokuenzler.com/blog/1526/check-mysql-slavestatus-monitoring-supports-replica-and-slave-replications https://www.claudiokuenzler.com/blog/1526/check-mysql-slavestatus-monitoring-supports-replica-and-slave-replications The latest release of check_mysql_slavestatus supports both MySQL and MariaDB replications and is backward compatible. Sun, 22 Mar 2026 08:06:00 +0000 https://www.claudiokuenzler.com/blog/1525/how-to-code-successful-games-jili-way https://www.claudiokuenzler.com/blog/1525/how-to-code-successful-games-jili-way How Jili Games have become successful in creating responsive and entertaining online casino games. Fri, 20 Mar 2026 06:15:15 +0000 https://www.claudiokuenzler.com/blog/1524/wordpress-elementor-mysterious-500-server-error https://www.claudiokuenzler.com/blog/1524/wordpress-elementor-mysterious-500-server-error The WordPress website builder Elementor ran into mysterious server errors (500 error) when trying to update a site. Fri, 06 Mar 2026 15:05:18 +0000 https://www.claudiokuenzler.com/blog/1523/update-openwrt-firmware-reboot-fixed-packet-loss-lan https://www.claudiokuenzler.com/blog/1523/update-openwrt-firmware-reboot-fixed-packet-loss-lan An OpenWRT router showed significant packet losses on the internal LAN. Time to update and reboot the device. Fri, 20 Feb 2026 11:12:07 +0000 https://www.claudiokuenzler.com/blog/1522/debian-13-trixie-ssh-service-reload-error-cannot-bind-address https://www.claudiokuenzler.com/blog/1522/debian-13-trixie-ssh-service-reload-error-cannot-bind-address In Debian 13 (Trixie), a service reload of the SSH service runs into an error and service fails. Wed, 18 Feb 2026 12:03:56 +0000 https://www.claudiokuenzler.com/blog/1520/monitoring-zfs-pools-detect-alert-spare-drive-in-use https://www.claudiokuenzler.com/blog/1520/monitoring-zfs-pools-detect-alert-spare-drive-in-use The check_zpools monitoring plugin now detects and alerts when a spare drive is in use in a ZFS Pool. Fri, 13 Feb 2026 16:17:06 +0000 https://www.claudiokuenzler.com/blog/1519/mysql-client-command-shell-script-error-2026-ssl-is-required https://www.claudiokuenzler.com/blog/1519/mysql-client-command-shell-script-error-2026-ssl-is-required After a Debian distribution upgrade, Shell scripts using the mysql command stopped working. An error related to TLS/SSL requirement shows up instead. Thu, 22 Jan 2026 12:09:47 +0000 https://www.claudiokuenzler.com/blog/1518/fixing-solaredge-modbus-pymodbus-error-after-debian-upgrade https://www.claudiokuenzler.com/blog/1518/fixing-solaredge-modbus-pymodbus-error-after-debian-upgrade After a Debian distribution upgrade, a Python script using solaredge-modbus library stopped working. Sun, 11 Jan 2026 15:16:55 +0000 https://www.claudiokuenzler.com/blog/1517/check-smart-6.17.0-fix-ata-error-count-add-areca-multi-drive-support https://www.claudiokuenzler.com/blog/1517/check-smart-6.17.0-fix-ata-error-count-add-areca-multi-drive-support The newest release, 6.17.0, contains a fix and an enhancement from two individual open source contributors. Mon, 15 Dec 2025 19:05:21 +0000 https://www.claudiokuenzler.com/blog/1516/nginx-error-debian-distribution-upgrade-unknown-directive-rewrite-by-lua-block https://www.claudiokuenzler.com/blog/1516/nginx-error-debian-distribution-upgrade-unknown-directive-rewrite-by-lua-block During a distribution upgrade from Debian 11 to 12, the Nginx LUA module got removed and caused a configuration error in Nginx. Thu, 11 Dec 2025 09:49:41 +0000 https://www.claudiokuenzler.com/blog/1515/netfilter-persistant-iptables-restore-error-ipset-does-not-exist https://www.claudiokuenzler.com/blog/1515/netfilter-persistant-iptables-restore-error-ipset-does-not-exist iptables-restore did not restore the persistent iptables rules after a reboot. Tue, 02 Dec 2025 21:06:53 +0000 https://www.claudiokuenzler.com/blog/1514/check-ilorest-hpe-proliant-server-power-usage-metrics https://www.claudiokuenzler.com/blog/1514/check-ilorest-hpe-proliant-server-power-usage-metrics The latest release 1.2.1 of the hybrid monitoring plugin check_ilorest adds power usage metrics of HPE ProLiant servers. Wed, 19 Nov 2025 13:21:40 +0000 https://www.claudiokuenzler.com/blog/1513/mariadb-mysql-secure-installation-socket-authentication-fails-error-1146 https://www.claudiokuenzler.com/blog/1513/mariadb-mysql-secure-installation-socket-authentication-fails-error-1146 Attempted to switch to MariaDB Socket Authentication but mysql_secure_installation failed with MySQL Error 1146 (42S02). Sat, 15 Nov 2025 07:00:32 +0000 https://www.claudiokuenzler.com/blog/1512/fixing-prometheus-scrape-error-on-ingesting-samples-different-value-same-timestamp https://www.claudiokuenzler.com/blog/1512/fixing-prometheus-scrape-error-on-ingesting-samples-different-value-same-timestamp The Prometheus metrics, including the HELP AND TYPE lines, must follow some rules. Or you run into scraping errors. Fri, 14 Nov 2025 14:10:41 +0000 https://www.claudiokuenzler.com/blog/1510/check-ilorest-new-hardware-monitoring-plugin-for-hpe-proliant-servers https://www.claudiokuenzler.com/blog/1510/check-ilorest-new-hardware-monitoring-plugin-for-hpe-proliant-servers check_ilorest is an open source monitoring plugin to monitor the hardware health of HPE ProLiant servers. It supports integration into classic monitoring systems as well as Prometheus metrics output for scrapers. Tue, 28 Oct 2025 19:02:11 +0000 https://www.claudiokuenzler.com/blog/1509/how-to-fix-opendkim-testkey-dns-query-timeout https://www.claudiokuenzler.com/blog/1509/how-to-fix-opendkim-testkey-dns-query-timeout When the opendkim-testkey command runs into errors and shows dns query time out, it could be related to the default setting to use the DNS Root servers for queries. Wed, 22 Oct 2025 08:47:35 +0000 https://www.claudiokuenzler.com/blog/1508/how-to-monitor-valkey-aws-memorydb-user-credentials-tls https://www.claudiokuenzler.com/blog/1508/how-to-monitor-valkey-aws-memorydb-user-credentials-tls Existing monitoring plugins will not work on Valkey with TLS and user authentication enabled. Time to fix this! Thu, 25 Sep 2025 06:10:38 +0000 https://www.claudiokuenzler.com/blog/1507/improving-blog-tags-switching-sql-query-function-like-vs-regexp https://www.claudiokuenzler.com/blog/1507/improving-blog-tags-switching-sql-query-function-like-vs-regexp By switching the SQL query from LIKE to REGEXP, blog tag filtering was improved. Tue, 23 Sep 2025 07:05:17 +0000 https://www.claudiokuenzler.com/blog/1506/systemd-service-not-starting-on-centos-rhel-el7-works-on-newer-releases https://www.claudiokuenzler.com/blog/1506/systemd-service-not-starting-on-centos-rhel-el7-works-on-newer-releases A Systemd service refused to start under Enterprise Linux (EL) 7 - but the same service unit worked fine under newer EL releases. Thu, 18 Sep 2025 13:25:44 +0000 https://www.claudiokuenzler.com/blog/1505/regression-found-varnish-enterprise-plus-6.0.16r2 https://www.claudiokuenzler.com/blog/1505/regression-found-varnish-enterprise-plus-6.0.16r2 A regression was found in the latest Varnish Enterprise (varnish-plus) package 6.0.16r2. Mon, 15 Sep 2025 13:21:07 +0000 https://www.claudiokuenzler.com/blog/1504/fixing-perl-strict-errors-haproxy-monitoring-plugin https://www.claudiokuenzler.com/blog/1504/fixing-perl-strict-errors-haproxy-monitoring-plugin check_haproxy.pl is a monitoring plugin to monitor HAProxy. In new systems, the plugin could throw Perl errors. Let us fix this. Fri, 12 Sep 2025 13:40:30 +0000 https://www.claudiokuenzler.com/blog/1503/fixing-broken-snmp-monitoring-virtual-firewall-after-checkpoint-vsx-upgrade https://www.claudiokuenzler.com/blog/1503/fixing-broken-snmp-monitoring-virtual-firewall-after-checkpoint-vsx-upgrade After Checkpoint VSX was upgraded to R81.20, SNMP interface monitoring on virtual firewalls (VS) stopped working. Fri, 05 Sep 2025 12:11:34 +0000 https://www.claudiokuenzler.com/blog/1502/how-to-allow-all-icmp-types-codes-ec2-security-group-terraform https://www.claudiokuenzler.com/blog/1502/how-to-allow-all-icmp-types-codes-ec2-security-group-terraform With the aws_security_group module, security groups (firewall rules) can be created using Terraform. Mon, 01 Sep 2025 09:20:05 +0000 https://www.claudiokuenzler.com/blog/1501/prometheus-process-exporter-comm-name-groupname-label-15-characters https://www.claudiokuenzler.com/blog/1501/prometheus-process-exporter-comm-name-groupname-label-15-characters Using the Comm variable for process names in Prometheus Process Exporter might lead to missing metrics. Here is why and how to fix it. Thu, 28 Aug 2025 10:30:02 +0000 https://www.claudiokuenzler.com/blog/1500/halftime-report-20-years-working-with-linux-40-years-old https://www.claudiokuenzler.com/blog/1500/halftime-report-20-years-working-with-linux-40-years-old This year marks 20 years that I work with Linux servers. Coincidentally I also turned 40 years old. Time for a quick breather and review. Tue, 26 Aug 2025 10:03:55 +0000 https://www.claudiokuenzler.com/blog/1499/how-to-create-dynamic-redirect-rules-multi-domain-cloudflare https://www.claudiokuenzler.com/blog/1499/how-to-create-dynamic-redirect-rules-multi-domain-cloudflare This tutorial shows how to create dynamic redirect rules in Cloudflare working for multiple matching domains. Mon, 25 Aug 2025 13:22:30 +0000 https://www.claudiokuenzler.com/blog/1498/haproxy-option-httpchk-headers-body-end-version-string-unsupported https://www.claudiokuenzler.com/blog/1498/haproxy-option-httpchk-headers-body-end-version-string-unsupported If you relied on the option httpchk in HAProxy configurations, you might have to adjust the HTTP check on newer HAProxy versions. Fri, 22 Aug 2025 13:21:55 +0000