Built by Dpro GmbH, in Vienna.

Why "Grenzer"

The Grenzer were border guards of the Habsburg Empire's Military Frontier in the 18th century — a dedicated line of defense along the empire's edge. The name carries directly into the product: just as the Grenzer guarded the empire's borders, Grenzer guards your server's.

What we're building

CSF (ConfigServer Security & Firewall) has protected Linux servers for years, but its architecture — Perl, iptables, a design largely unchanged since the 2000s — hasn't kept pace. Grenzer is a from-scratch replacement: written in Go, built on nftables, with an optional AI-augmented detection layer and an MCP server so AI assistants can work with your server's security data directly.

The core — firewall and Login Failure Detection — is free, forever. We believe the daily-driver protection every server needs shouldn't have a price tag. The Pro tier funds continued development through the professional features that hosting companies and agencies specifically need: AI detection, multi-tenant backup, and cPanel/WHM integration.

The company

Dpro GmbH is an Austrian company based in Vienna's 1st district (Innere Stadt).

Get in touch

Questions about Grenzer, Pro licensing, or partnering with us for a hosting/agency deployment — email info@dpro.at.