B.O.F.H. - Benevolent Operator of Faultless Hardware

Testing firewall rules continuously with Zabbix: what should — and shouldn't — be reachable

Monitoring , Security

Network segmentation looks great on the diagram: the DMZ can’t reach the database VLAN, office workstations can’t reach server management interfaces, backups are reachable only from the backup server. Then a year passes. Someone adds a temporary “any-any” rule to debug an issue. A firewall migration converts policies slightly differently. A new VLAN is created by copying an old one.

Monitoring HPE Managed PDUs in Zabbix: power, outlets, breakers and rack sensors

Monitoring , Datacenter

A PDU is the least glamorous box in the rack — until a breaker trips and half the servers lose one power supply, or a new server pushes a phase over its limit and the whole rack goes dark. Managed PDUs measure all of this. The data just needs to end up somewhere people actually look.

How to monitor your home internet connection — and prove it to your ISP

Networking , Monitoring

The video call freezes, the game lags, the trading terminal reconnects. A speed test five minutes later shows 500 Mbit/s and everything looks fine. You call your provider, they “see no issues on the line”, and suggest restarting the router.

Monitoring disk health on VMware ESXi with smartctl

VMware , Monitoring

Standalone ESXi hosts and small vSphere clusters often run on local SATA or SAS disks — in a homelab, a branch office, or a backup host. When one of those disks starts to fail, you want to know about it from your monitoring, not from a datastore that suddenly goes read-only.

gWebTail: tail -f in the browser for teams without SSH access

Monitoring , Tools

A familiar scene: a new build is deployed to a test server and a developer asks “can you send me the log?”. Someone with SSH access logs in, runs tail -f, copies a chunk into a chat — and ten minutes later does it again.

ESXi disk health in Zabbix: SMART for SATA, health log for NVMe

VMware , Monitoring

The standard Zabbix templates for VMware (VMware and VMware Hypervisor, using the vSphere API) are great for CPU, memory, datastores and VM status. What they don’t tell you is how the physical disks in a standalone ESXi host are doing. You learn that a disk failed when a datastore goes offline — not a week earlier, when the drive started reallocating sectors.

Are your network config backups actually working? Oxidized + Zabbix

Monitoring , Networking

Oxidized is the de facto open-source tool for backing up network device configurations. It logs into switches, routers and firewalls — Cisco, Juniper, MikroTik, Fortinet, HPE/Aruba and dozens of others — downloads the running config and stores every version in Git. When a device dies or someone breaks the config, you have the last known good version and a diff of what changed.

Traefik 4xx/5xx errors in Zabbix without Prometheus

Monitoring , Kubernetes

Traefik sits in front of a lot of applications: as a Docker reverse proxy, as a Kubernetes ingress controller, or as an edge router on a single VM. That makes it the best place to see whether your applications are healthy from the user’s point of view — every failed request passes through it.

Monitoring Wazuh agents in Zabbix via the REST API

Monitoring , Security

Wazuh is a popular open-source SIEM/XDR: agents on servers and workstations collect logs, file-integrity events and vulnerability data, and send them to the Wazuh manager. It works well — as long as the agents are actually connected.