5ok on 5ok — sysadmin, devops, hosting

Systems administration

Mon, 01 Jan 0001 00:00:00 +0000

We’ve been running Linux servers since 2003. We started out as employees managing systems, and later found each other here. Today, sysadmin work is our bread and butter.

Who it’s for

We work with companies that have their own servers or VPS that someone needs to keep up. A typical client has 5–50 machines running a mix of web, databases, internal applications. They usually don’t need a full sysadmin team — but they need someone to respond, keep a firm hand on the infrastructure, and work through their requirements with them.

Teltonika Networks

Mon, 01 Jan 0001 00:00:00 +0000

Design

Teltonika Networks has its own R&D team in Kaunas, Lithuania, developing new products and expanding the existing lineup with new features as the market needs them.

Manufacturing

Devices are manufactured and assembled in-house at Teltonika’s own facility in Vilnius, Lithuania. In-house manufacturing means tight quality control — every unit is tested before it leaves the warehouse.

Support

Teltonika’s tech support and R&D teams sit side by side, which keeps response times short when issues come up.

Custom hosting

Mon, 01 Jan 0001 00:00:00 +0000

Custom hosting sits between shared hosting and a full IT department. If your site runs fine on a €5/mo webhost, you don’t need us. But if your project has grown and something cracks every other month — too big for shared, too small for an in-house team — we’re here.

Who it’s for

E-shops, SaaS, B2B portals, custom apps that need more than PHP-FPM on a shared server. Clients with 5 000 to 500 000 visits/month who need stability, performance, and someone who can respond.

Programming

Mon, 01 Jan 0001 00:00:00 +0000

We’ve been writing code for more than 20 years. Currently mostly in Python and PHP. We like small, sharp projects — a backend for an internal app, an integration between two systems, an automation that saves 20 hours a month.

Our favourite projects

Integrations — got systems that should be talking to each other? We write the glue code.
Internal tools — admin panels, dashboards, back-office tools.
API backends — when you need a REST or GraphQL endpoint for a frontend or mobile team.
Migration scripts — moving data from a legacy system, validation, reconciliation.

What we like

Good specs. Short iterations. No meetings that could have been an email. Clients who can say “no, we don’t need that” - that’s rare.

Teltonika RUT300

Mon, 01 Jan 0001 00:00:00 +0000

The RUT300 is a small, but powerful Ethernet router perfect for challenging industrial networking tasks as well as general networking applications.

Teltonika RUT360

Mon, 01 Jan 0001 00:00:00 +0000

RUT360 is an updated version of all-time best-seller RUT240. This compact industrial cellular router offers a possibility to connect to the internet using cellular, Wi-Fi, and wired networks.

Teltonika RUT950

Mon, 01 Jan 0001 00:00:00 +0000

RUT950 is a high-performance industrial 4G LTE Wi-Fi router designed as a Main/Backup internet source and guarantees a reliable internet connection with high data throughput and data redundancy.

Teltonika RUT951

Mon, 01 Jan 0001 00:00:00 +0000

RUT951 features dual-SIM cellular connectivity combined with Wi-Fi and four Ethernet interfaces to meet the needs of the most varied IoT scenarios. Powered by RutOS, this router offers advanced customization options, automation features, and top-level security for your solution.

Teltonika RUT955

Mon, 01 Jan 0001 00:00:00 +0000

RUT955 is a highly reliable industrial LTE Cat 4 router that delivers high performance and GNSS location capabilities.

Ethernet, Digital, and Analogue I/O, RS232, RS485, GNSS (GPS), microSD, and USB interfaces allow for an incredible variety of industrial application scenarios.

Teltonika RUTX08

Mon, 01 Jan 0001 00:00:00 +0000

RUTX08 is a durable and powerful Ethernet-to-Ethernet industrial VPN router that runs on RutOS - an advanced OpenWRT based operating system. It has four Gigabit Ethernet ports with speeds up to 1000 Mbps. A rugged aluminum housing and industrial network- ing protocol support make RUTX08 a perfect choice for professional applications. These powerful specifications combined with RutOS software features, such as multiple supported VPN services, advanced Firewall, and Remote Management System (RMS) make this device a superb performer, where no cellular or Wi-Fi connectivity is required.

Teltonika RUTX09

Mon, 01 Jan 0001 00:00:00 +0000

RUTX09 is LTE-A Cat 6 cellular IoT router with Dual-SIM, Carrier Aggregation, and 4 Gigabit Ethernet interfaces. RUTX09 is designed as a Main/Backup internet source offering cellular speeds up to 300 Mbps, where steady connection and high data throughput is necessary. It has plenty of processing capacity for custom applications on the OpenWrt based RutOS system. Plenty of security features are available, like Firewall, VPN, IPsec, SNMP, Content Filtering for maximized safety. This product is compatible with our Remote Management System for convenient monitoring, maintenance, and data collection.

Teltonika RUTX10

Mon, 01 Jan 0001 00:00:00 +0000

RUTX10 is Enterprise router specially for small to mid-size office applications. It comes with Dual Band Wi-Fi 5 802.11ac, which is very suitable for high data transmission and robust wireless performance. It has all the latest security features and allows remote monitoring and control. RUTX10 comes with highly functional & customizable RutOS based on OpenWRT. Synergy between hardware and software makes this device an amazing performer in Enterprise solutions.

Teltonika RUTX11

Mon, 01 Jan 0001 00:00:00 +0000

This powerful LTE Cat 6 cellular router is designed for professional applications requiring reliable, fast connection and high data throughput. The RUTX11 is equipped with four Gigabit Ethernet ports, AC Wi-Fi, Bluetooth LE, and is EN 45545-2-certified, making it approved for use in passenger trains across Europe.

Teltonika RUTX12

Mon, 01 Jan 0001 00:00:00 +0000

This powerful dual LTE Cat 6 router is a great fit for mission-critical applications. Two cellular modems for dual simultaneous connections, seamless mobile service switching and load balancing features make this device irreplaceable in applications where losing connection is not an option.

Teltonika RUTX14

Mon, 01 Jan 0001 00:00:00 +0000

RUTX14 is the fastest single modem LTE-A Cat 12 router in the Teltonika Networks product range. With two SIM cards, Wave-2 dual-band Wi-Fi, five Gigabit Ethernet ports, and automatic failover, you may expect high compatibility, unbeatable network resilience, and exceptional speed.

Teltonika TRB142

Mon, 01 Jan 0001 00:00:00 +0000

TRB142 is an ultra-small, lightweight, and energy-efficient IoT gateway equipped with mission-critical LTE connectivity. TRB142 comes with a widely used RS232 interface for remote management of industrial devices, making it a reliable communicator for serial-based deployments.

Teltonika TRB145

Mon, 01 Jan 0001 00:00:00 +0000

TRB145 is an ultra-small, lightweight, and energy-efficient IoT gateway equipped with mission-critical LTE connectivity. Acting as a compact RS485 communicator, it comes with RS485 interface for remote management of industrial equipment.

Teltonika TRB245

Mon, 01 Jan 0001 00:00:00 +0000

Industrial LTE Cat 4 gateway packs all essential features for any industry: fast and reliable internet connection, combination of Ethernet and serial communication, secure power connector, I/O ports, and time synchronization services

TRB245 can be used to integrate modern and legacy industrial equipment in one solution via RS232 or RS485 interfaces.

Teltonika TRB255

Mon, 01 Jan 0001 00:00:00 +0000

TRB255 can be used to integrate modern and legacy industrial equipment into one solution via RS232, RS485 & Ethernet interfaces.

This industrial LTE Cat M1 & NB-IoT gateway is backward compatible to EGPRS (2G) networks. It can still be used with 2G network, however in case it gets shut down, there is a possibility to switch to LPWAN connectivity options.

Teltonika TRB500

Mon, 01 Jan 0001 00:00:00 +0000

TRB500 is a compact, energy-efficient 5G gateway for ultra-fast data transmission with ultra-low latency. Backward compatibility with 4G and 3G networks enables future-proofing solution infrastructures even in areas where 5G is not yet available.

Teltonika TRM240

Mon, 01 Jan 0001 00:00:00 +0000

TRM240 is an industrial-grade USB LTE Cat 1 modem with a rugged housing and an external antenna for better signal coverage. This product is perfect for upgrading existing industrial equipment with cost-efficient LTE connectivity.

Teltonika TRM250

Mon, 01 Jan 0001 00:00:00 +0000

TRM250 is an industrial-grade USB LTE Cat-M1/NB-IoT/EGPRS modem with a rugged housing and an external antenna for better signal coverage. This product is perfect for providing cost-efficient internet connectivity in remote monitoring applications.

Teltonika TSW100

Mon, 01 Jan 0001 00:00:00 +0000

TSW100 is an unmanaged Gigabit Ethernet switch supporting Power-over-Ethernet. Classified as power source equipment (PSE), it centralizes the power supply, providing up to 30 watts per port and reducing installation effort. Five Gigabit Ethernet ports provide an economical high-bandwidth solution for a secure industrial Ethernet network.

Teltonika TSW110

Mon, 01 Jan 0001 00:00:00 +0000

TSW110 is an unmanaged layer 2 Ethernet switch. This tiny but rugged professional device enables industrial high-bandwidth applications with a reliable data connection. It has five Gigabit Ethernet ports to connect equipment to the network and supports wide power supply voltages (9-30 V).

Teltonika TSW200

Mon, 01 Jan 0001 00:00:00 +0000

TSW200 is an industrial Ethernet switch with 2 SFP ports for long-range Fiber-optic communication and 8 Gigabit Ethernet ports that support IEEE802.af and IEE802.3at Power-over-Ethernet standards. Classified as power source equipment (PSE), it enables the centralization of the power supply, providing up to 30 watts per port and reducing the effort to install power.

Teltonika RUT200

Mon, 01 Jan 0001 00:00:00 +0000

RUT200 is a compact industrial cellular router that provides reliable, mission-critical connectivity in rigorous conditions common in industries like automation, transportation, and manufacturing. This model is equipped with 4G LTE, Wi-Fi, and two Ethernet ports, making it ideal for quickly setting up primary and backup connectivity with remote management capabilities.

Teltonika RUT241

Mon, 01 Jan 0001 00:00:00 +0000

The RUT241 is a compact, industrial-grade cellular router designed for reliable and versatile connectivity in IoT and M2M applications. RUT241 features rugged design, multiple connection interfaces including 4G LTE, Wi-Fi, and two Ethernet ports. With support for automatic WAN failover and advanced RutOS software, the RUT241 enables continuous connectivity and solution automation through its digital inputs and outputs. RUT241 includes eSIM™ functionality, allowing up to seven eSIM™ profiles alongside a physical SIM card. A non-eSIM™ version is also available.

Teltonika RUT906

Mon, 01 Jan 0001 00:00:00 +0000

Cellular 4G router for industrial IoT applications, supporting serial interfaces RS232 and RS485, MQTT, BACnet, I/Os, Ethernet, and more. This cellular router is equipped with GNSS and failsafe features such as Dual SIM, auto-failover, and backup WAN.

Teltonika RUT956

Mon, 01 Jan 0001 00:00:00 +0000

RUT956 is an industrial router that combines cellular, Wi-Fi, and wired connectivity options with automatic WAN failover and GNSS capabilities. Serial communication interfaces enable integrating more varied devices into the solution ecosystem, while I/O and advanced RutOS software facilitate equipment control, automation, and event notifications.

Teltonika RUTX50

Mon, 01 Jan 0001 00:00:00 +0000

RUTX50 is a dual-SIM multi-network router offering 5G mobile communication for high-speed and data-heavy applications. Together with 5x Gigabit Ethernet ports and dual-band Wi-Fi, it provides data connection redundancy with auto-failover. Backward compatibility and multiple interfaces allow for long-term expandability and upgrading options.

Teltonika TAP200

Mon, 01 Jan 0001 00:00:00 +0000

Equipped with dual-band technology, fast roaming, and an RJ45 port with PoE-in functionality, the Teltonika Networks TAP200 is a Wi-Fi 5 wireless access point designed to enhance Wi-Fi coverage in medium-density spaces where high network performance is essential. The TAP200 features an integrated mounting bracket for quick and easy installation, and a sleek design to seamlessly blend into retail, enterprise, or any other environment.

Teltonika TRB140

Mon, 01 Jan 0001 00:00:00 +0000

TRB140 is an ultra-small, lightweight, and energy-efficient IoT gateway with mission-critical LTE Cat 4 and Gigabit Ethernet connectivity options. Linux environment offers a high degree of customization. This IoT communicator is perfect for projects and applications where a single device must be upgraded with reliable and secure internet connectivity.

Teltonika TSW010

Mon, 01 Jan 0001 00:00:00 +0000

TSW010 Ethernet switch offers the most affordable way to extend network connectivity to multiple Ethernet devices. Five 10/100 Mbps Ethernet ports ensure stable and reliable connectivity, sufficient for most industrial applications where high throughput is not required.

Teltonika TSW030

Mon, 01 Jan 0001 00:00:00 +0000

The TSW030 is a cost-efficient unmanaged Ethernet switch, featuring eight 10/100 RJ45 ports and integrated DIN rail mounting. This compact and rugged 8-port switch includes a 2-pin power input and low power consumption of up to 0.5 W when idle and a maximum of up to 1.5 W. These make this plug-and-play switch perfect for industrial applications requiring to connect up to eight devices.

Teltonika TSW202

Mon, 01 Jan 0001 00:00:00 +0000

TSW202 is a managed PoE+ Ethernet switch offering granular Layer 2/3 network management alongside centralized power distribution. Its 8 Gigabit PoE+ ports (up to 30 W each, 240 W total budget) and 2 SFP uplinks support VLAN, STP/RSTP, QoS, SNMP, and industrial protocols including EtherNet/IP, PROFINET (Class B), and MRP — built for demanding, security-conscious industrial networks.

Teltonika TSW210

Mon, 01 Jan 0001 00:00:00 +0000

TSW210 is an Ethernet switch that offers a great combination of Gigabit Ethernet and SFP. Eight Ethernet ports enable connecting multiple devices to the network quickly and easily without any further configuration. SFP allows including far apart devices while maintaining high-speed rates and reliability.

Why we moved to k3s

Thu, 18 Jun 2026 00:00:00 +0000

Three years ago we set up full Kubernetes on a set of our own servers. It was the right call — at the time. We had a team that knew what it was doing and applications that benefited.

Over time it became clear we were using a fraction of what Kubernetes offered. And maintaining the control plane itself started eating more time than running the applications on top of it.

Hosting for an e-shop doing 40,000 orders a month

Wed, 20 May 2026 00:00:00 +0000

The problem

An e-shop built on a custom PHP application ran on managed hosting that fell over during every campaign. Average TTFB 1.8 s, over 6 s at peak. The hosting provider’s answer was that they were “exceeding plan limits”.

What we did

We built dedicated infrastructure across three machines:

App server — Nginx + PHP-FPM, pool settings tuned to the real load profile.
DB server — PostgreSQL with a replica, shared_buffers and work_mem sized to the dataset rather than left at defaults.
Cache layer — Varnish in front of the application for anonymous requests, Redis for sessions and application cache.

The migration ran over a weekend with a 12-minute window for the DNS switch and final database sync.

Bare-metal to Proxmox with no downtime

Mon, 11 May 2026 00:00:00 +0000

The client had four physical servers, one application each. A classic 2015–2018 setup: one server = one service, no virtualisation, no backups beyond rsync to a NAS.

The brief: get it onto Proxmox, gain snapshots and live migration, and keep downtime under a few minutes per service.

The plan

The approach we use almost every time:

Build a new Proxmox cluster alongside (three nodes, Ceph pool).
For each service create a VM and deploy from configuration management — not by cloning the old disk.
Run both instances in parallel, synchronise data one-way.
Switch DNS / load balancer, watch, keep the old instance on standby for a week.

Point 2 matters. Cloning a physical disk into a VM (P2V) is fast, but it carries ten years of sediment with it — old packages, manual /etc edits nobody documented. If you have Ansible, rebuild instead.

systemd timers instead of cron

Sat, 21 Mar 2026 00:00:00 +0000

Cron has one enormous advantage: everyone knows it. And one disadvantage: when it fails, you find out by email to root@localhost, which nobody reads.

systemd timers fix exactly that.

The basics

A timer is two files — .service (what runs) and .timer (when).

# /etc/systemd/system/backup.service
[Unit]
Description=Nightly backup
After=network-online.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/backup.sh

# /etc/systemd/system/backup.timer
[Unit]
Description=Run backup nightly

[Timer]
OnCalendar=*-*-* 02:30:00
RandomizedDelaySec=15m
Persistent=true

[Install]
WantedBy=timers.target

What cron can’t do

Persistent=true — if the machine was off at the scheduled time, the job runs at next boot. Cron just skips it.

Remote monitoring network for a water utility

Thu, 12 Mar 2026 00:00:00 +0000

The brief

Sixty pumping stations and reservoirs scattered across a region, each with a PLC nobody sees until something breaks. The goal: get PLC data into the control room and have real-time visibility.

The solution

We deployed a Teltonika TRB245 at each site — an LTE gateway with RS485 that:

Reads registers from the PLC over Modbus RTU.
Publishes them via MQTT to a central broker.
Maintains a permanent WireGuard tunnel back to HQ for remote PLC access.

Centrally: Mosquitto → Telegraf → Prometheus → Grafana. Alerts reach dispatch via email and an SMS gateway.

A small team of Linux people from Bratislava

Mon, 01 Jan 0001 00:00:00 +0000

We started in 2004 as employees. Today we run infrastructure for companies across Slovakia.

Over the years we’ve learned one thing: most problems in IT aren’t technical. They’re a misunderstanding about what should be built, or a system nobody understands after its original author leaves.

That’s why we write documentation. That’s why we hand over projects so someone else can take them on. And that’s why we’d rather turn down work that isn’t a fit than do it badly.

Get in touch

Mon, 01 Jan 0001 00:00:00 +0000