Firewall Rule Generator — iptables, nft, UFW
Generate firewall rules for iptables, nftables, and UFW from IP, port, protocol, and action inputs.
How it works
- 1Configure your options above
- 2Click "Generate Firewall Rules" — processing happens in your browser
- 3Copy or download the result
What to do next
About Firewall Rule Generator
Firewall Rule Generator is the kind of utility you bookmark and reach for when you need it. Generate firewall rules for iptables, nftables, and UFW from IP, port, protocol, and action inputs. It loads quickly, works on any modern browser, and produces a result you can download or copy in a single click.
Architecturally, Firewall Rule Generator is a single-page client. The processing layer is standard browser APIs; the UI is a thin React shell on top. Inputs flow through the engine and the output is returned to the browser as a Blob you can save or copy. The 0 MB cap is the only hard limit and it exists to keep memory usage stable on every device.
Firewall Rule Generator performs the transformation entirely inside the JavaScript runtime. Your file lives in the tab's memory while the engine works on it; the result lives in the tab's memory until the browser triggers the download. Both are released when the tab closes, the way every browser tab releases its memory.
The heaviest users of Firewall Rule Generator tend to be marketers running campaigns, creators experimenting with formats and researchers gathering quick references. Each group brings slightly different expectations to the tool, but the same single-page architecture serves every one of them with the same response time.
Firewall Rule Generator works well as a bookmarked utility you reach for when you need it. The first visit shows you what the tool does; the second is when you realise it is a low-friction option for the task and worth keeping in your tab list.
The hard constraints are easy to remember. Maximum input: 0 MB. Multiple files per run: no — one input at a time, by design, to keep results predictable. The same controls apply on every run.
Once you have used Firewall Rule Generator, the natural next steps depend on what you are doing with the result. Common follow-ups include Web Security Checklist, OWASP Top 10 Checklist, and CSP Header Validator. These are surfaced on the page so you do not have to hunt the catalog manually.
Firewall Rule Generator is honest about scope: it handles a single, well-defined web and productivity utility step. Specialist edge-case work — uncommon formats, very large inputs, or pipelines that need scripting — is what dedicated desktop apps are for. This page handles the common case quickly.
The download is delivered as a clearly named file the moment processing completes — no email link, no "your result will be ready in 5 minutes" queue, no expiry timer. The file is generated in your browser and saved by your browser's normal download flow.
Some background on the design choices behind Firewall Rule Generator: every option you see on the page is there because a real workflow needs it, and every option that is not shown has been deliberately omitted to keep the common case fast. The bias is toward minimal-but-complete.
As a single-page tool, Firewall Rule Generator stays focused on one web and productivity utility step. Multi-step workflows are composed by chaining adjacent tools — each tool produces a standard file the next one can read directly, so a longer pipeline is just a sequence of short tab-and-tab visits.
A few practical tips that experienced users of Firewall Rule Generator pick up over time. First, keep your default browser updated — the engine relies on standard web APIs and newer browser versions are noticeably faster than ones from a few years ago. Second, close other heavy tabs before processing a large input; the engine shares CPU and memory with whatever else is open. Third, if you re-run the same kind of job often, your last-used settings are remembered for the rest of the tab session, so subsequent runs are essentially one click.
If Firewall Rule Generator appears to hang, the engine is almost certainly still working — large inputs simply take longer to process inside a browser than they would on a server with multi-core scheduling. For inputs near the 0 MB cap, give it up to a minute on a typical laptop before assuming something is stuck.
Firewall Rule Generator is intentionally narrow in scope so the common case is fast and the result is predictable. If you ever need a variation it does not cover, browse the rest of the catalog — there is a good chance an adjacent tool already exists, and switching between tools is just a matter of opening another tab.
How it works
- 1Open the Firewall Rule Generator workspace above. The interface is a single page, so there is nothing to navigate.
- 2Drop a web utility file onto the upload area, or click to pick one from your device.
- 3Pick any non-default settings you need. Most users leave the defaults alone for the first run and only revisit if the result needs tuning.
- 4Hit the run button. standard browser APIs does the work in your browser tab.
- 5Grab the output as soon as the run completes. You can also copy the result instead of downloading if the next tool in your workflow accepts pasted input.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Sanity-check a webhook response while debugging using Firewall Rule Generator.
- Plan content without paying for a SaaS dashboard.
- Pull a quick reference number for a status update.
- Preview how a result looks before deploying it.
- Create a placeholder image for a wireframe.
- Generate a temporary asset for a social post.
- Run a one-off check during a meeting without context-switching.
- Compare two product variations side by side.
- Generate a campaign asset in seconds for a quick test.
- Audit a marketing page before launch.
FAQ
Which firewalls?
Generates rules for iptables (Linux), nftables (modern Linux), and UFW (Ubuntu/Debian).
CIDR notation?
Use CIDR notation for IP ranges, e.g., 192.168.1.0/24 for a /24 subnet.
Port ranges?
Specify ranges with colon (8000:9000) and multiple ports with commas (80,443).
Private?
Yes — generated locally. Rules are not applied to any system.
DROP vs REJECT?
DROP silently discards packets; REJECT sends an error response back. DROP is stealthier.
Are rules applied?
No — the tool only generates the commands. You must run them on your server manually.
Which file formats does Firewall Rule Generator accept?
The accepted formats are listed in the upload area on the tool itself. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.
Does Firewall Rule Generator need an internet connection to run?
Once the page is loaded, Firewall Rule Generator can complete jobs without an active internet connection — the engine is bundled with the page, so there is no per-job network call. The initial page load does require a connection (to fetch the static assets), but after that you can disconnect entirely and the tool will still work. This is a side-effect of the local-first architecture, not a deliberate "offline mode" feature.
Is Firewall Rule Generator mobile-friendly?
Firewall Rule Generator runs in any modern mobile browser — Safari, Chrome, Firefox and the in-app browsers in most messaging apps all support the underlying APIs. Performance depends on the device: a recent phone handles typical inputs nearly as fast as a laptop, while older devices may take a few seconds longer near the 0 MB ceiling. The interface lays out cleanly on small screens, so you do not need to pinch-zoom to see the controls.
Can I self-host Firewall Rule Generator for my team?
Firewall Rule Generator is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (standard browser APIs) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
Does Firewall Rule Generator work with screen readers?
Firewall Rule Generator uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.
Can I trust the output of Firewall Rule Generator for important work?
Firewall Rule Generator is built on standard browser APIs, which is the same class of engine used by professional web and productivity utility pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Are there any usage limits on Firewall Rule Generator?
Inputs are capped at 0 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run Firewall Rule Generator as often as you need; every run produces a full-quality result.