Pilot program · until 30 Nov 2026 6 months free of charge for up to 5 servers, afterwards €18.50 instead of €37.
Attackers have AI now. Your servers have Sentinel.
Attacks are automated now: AI hunts for vulnerabilities around the clock. Sentinel answers in kind. An AI reads the status of your servers, plans the maintenance, and writes the report. Vetted code carries it out, backed up before every update and rolled back automatically if something fails.
Notifies you via Email Slack Microsoft Teams Google Chat Telegram Webhook
Works with Ubuntu Debian Docker nginx Caddy Apache WordPress Hetzner Cloud
All featuresAttacks are automated now. Updates, sadly, are not.
Attackers have AI search for vulnerabilities and exploit them, around the clock. A security update that sits until the next maintenance window is an open door for that long.
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80–90%
of the attack steps in an espionage campaign were carried out by an AI itself in 2025, from finding the vulnerability to exfiltrating the data.
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17%
of German companies had an AI-related attack within twelve months.
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43 days
is the median time it takes the companies studied to fully close an actively exploited vulnerability.
1 hour. That is how long it takes with Sentinel, as a rule, until a security update is installed. At night too, on weekends too.Check every 10 minutes, trigger every hour, usually without a maintenance window
When Ubuntu or Debian releases a security update, Sentinel records the package state and installs it, as far as the risk class allows, without waiting for the maintenance window. How independently Sentinel may act is for you to decide.
How Sentinel works: monitoring, updates, audit log
A sentry for every server. Nothing installed, every action logged.
Sentinel signs in over SSH with its own user. What it sees, does, and proves on the server comes in three steps.
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See.
every 10 minutes
Sentinel checks every server for pending security updates and shows in the exposure report which actively exploited vulnerabilities affect it. It does not find unknown vulnerabilities. It detects changes to accounts, keys, scheduled jobs, services, ports, and under /etc, and then calls in a human.
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Act.
usually within 1 hour
Before the update, Sentinel records the package state. Afterward it checks the same things as before, including your website in its own browser. Whatever is newly red gets rolled back. Anyone trying out passwords on SSH access is temporarily blocked.
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Prove.
every step
Every action is in the audit log, checksum-chained. For serious cases, Sentinel preserves the evidence and notifies you. In the morning, the AI sums up the night in a few sentences.
Everything about security, including what Sentinel does not cover
From real operations
104 security updates in 12 minutes.
A managed server running Ubuntu 18.04, 104 pending security updates. On 4 October 2026 at 03:11, Sentinel took over. By 03:23, everything was installed, checked, and logged.
Maintenance begins. Sentinel checks the server and records the package state.
130 packages installed, 104 of them security updates.
Reboot, then the same checks as before.
Done. Everything on record.
SENTINEL21–22 October 2026, summarized from the audit log
- seenThe day before: 12 security updates pending, among them PHP 8.1 against the php2shell vulnerability, CVSS 9.2 out of 10, on a customer’s server.
- actedIn the maintenance window: server checked, package state and configuration backed up, machine image created, 12 security updates installed, checked again.
- provenRun successful, checksum chained, vulnerability closed.
This run still waited for the window; Sentinel now installs security updates separately from it, usually within an hour. Not faster than Ubuntu. But faster than Monday. The whole night
Control: four levels, server by server
You decide how far Sentinel goes.
New servers start with watching only. Sentinel may do more only once you enable it, level by level. One click on the emergency stop halts everything.
Observe Start
Watches and reports. Does not intervene.
Cautious
Security updates and temporary blocks run automatically.
Normal
All updates in the maintenance window, with a backup before and the same check after.
Full
Reboots too, by your rule, and WordPress plugins on request.
Sentinel only sends commands from a catalog of 67 vetted actions and fixed checks. Each one goes through a deny list first.
The automation stops after the current step. Without the sudo rule on the server, Sentinel can no longer change anything there.
An upgrade to a new Ubuntu or Debian release cannot be rolled back. That is why Sentinel never starts one on its own.
The AI in Sentinel
AI on board. Not at the helm.
The AI explains maintenance plans, reads the evidence of serious cases, and writes the morning report. It never triggers an intervention: updates, blocks, and rollbacks follow rules that you can view and set.
Reads the evidence of serious cases. It writes down what happened and what it recommends.
Reviews maintenance plans. If it disagrees with the order, its objection is in the audit log.
Writes the morning report. The status of all servers in plain sentences, by email or chat.
Never triggers an intervention. Even malware that whispers instructions to the AI achieves nothing that way.
Sees no credentials. A filter removes recognizable keys and passwords beforehand.
All servers are running. One item needs attention.
All 8 servers are running stably. In the last 24 hours, Sentinel successfully completed 5 maintenance runs and installed 23 security updates in the process. An unknown SSH key was found on the shop server and should be reviewed. There are no other open items.
Pricing for Linux server maintenance
€37 per server. Instead of €100 to €150 with service providers.
One fixed price per server per month, AI included when the control center is hosted by us. Of that work, Sentinel takes over the routine: security updates, the check afterward, the rollback path, the audit log; outages outside maintenance and projects stay with you or your service provider.
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Observe
€14per server per month
Reports what it finds and changes nothing: vulnerabilities, attacks, certificates, and services, with a recommendation.
Cancel monthly
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The standard choice
Maintain
€37per server per month
Closes vulnerabilities, maintains, and locks attackers out, by your rules. With rollback and a report for every run.
Cancel monthly
Request a pilot place -
Fleet
€29per server per month
From 25 servers; from 100 servers, €22. For IT service providers with customer access and one report on the whole fleet.
12-month term; from 500 servers, €4 per server on a 24-month term
Pilot program: 10 places, 6 months free for up to 5 servers, then permanently €18.50 instead of €37. Apply by 30 November 2026
All prices net, plus VAT, only for entrepreneurs within the meaning of Section 14 of the German Civil Code (BGB); a contract is concluded only through a quote in text form.
All plans and the cost calculatorThe next step
Six months free of charge, in return for your feedback.
For the pilot program we are looking for ten companies that run Sentinel on up to five servers. No payment details, no automatic renewal, and afterwards a permanent €18.50 instead of €37 per server per month. Apply by 30 November 2026.
Prefer to talk directly? Martin Stroschein, Managing Director
+49 221 16834135 · info@limebyte.de
Developed in Cologne by LimeByte, the team for security assessments and penetration tests. Control center at Hetzner in Falkenstein, Germany. In use in our own operations since 10 September 2026.