# knock(1) — network port knocking client

> iOS port knocking client to open firewall ports on demand. (iPhone/iPad app by Jeffrey Cousens.)

- Source: https://appshunter.io/ios/app/knock1/id6762497209 (this page in markdown: same URL + `.md`)
- Developer: [Jeffrey Cousens](https://appshunter.io/developer/1877690927)
- Category: Utilities, Developer Tools
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: English
- Released: 2026-04-21
- Data updated: 2026-07-08
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/knock1/id6762497209/reviews.md

## What is knock(1)?

Knock is a minimal, native port-knocking client for iOS. Open ports in your firewall - SSH, VPN, admin panels - by sending a saved sequence from your iPhone.

Save named configurations with a host, a list of ports, a delay, and a timeout. Each port can be independently TCP or UDP. Run the sequence with a single tap and watch each knock's result stream in live.

FEATURES
• Save and reuse multiple host configurations
• Per-port TCP or UDP selection
• Configurable inter-packet delay and socket timeout
• Live per-port result display
• Clean SwiftUI interface, native look and feel
• No tracking, no analytics, no accounts

HOW IT WORKS
Port knocking is a technique for opening firewall ports on demand: your server watches for a specific sequence of connection attempts (for example, TCP/7000, UDP/8000, TCP/9000), and only opens a protected service like SSH after seeing the right pattern. knock(1) lets you send those sequences from your phone, allowing you to connect to your servers on the go.

COMPATIBLE
knock(1)'s behavior matches the reference jvinet/knock client - if your server runs knockd, knock(1) works out of the box.

PRIVACY
knock(1) connects only to the hosts you configure. It does not send telemetry, does not use analytics SDKs, and does not require an account. Your saved configurations stay on your device.

## Key features

- Save and reuse multiple host configurations
- Per-port TCP or UDP selection
- Configurable inter-packet delay
- Live per-port result display
- Native SwiftUI interface
- No tracking or analytics


## Frequently asked questions about knock(1)

### What is knock(1)?

knock(1) is a native iOS port-knocking client. It enables you to send a specific sequence of connection attempts from your iPhone to open ports on your server's firewall, such as for SSH or VPN access.

### How does knock(1) work?

Port knocking involves sending a predefined sequence of connection attempts to specific ports. Your server, running compatible software like knockd, detects this sequence and opens the desired service port, allowing you to connect.

### Can I configure individual ports in knock(1)?

Yes, knock(1) allows you to configure each port within a sequence independently. You can select whether each port uses TCP or UDP, and set custom delays and timeouts.

### Does knock(1) require an account?

No, knock(1) does not require any accounts. All your saved configurations are stored locally on your device, ensuring your privacy and security.

### Is knock(1) compatible with my server?

knock(1) is designed to be compatible with servers running the reference jvinet/knock client. If your server uses knockd, knock(1) should work out of the box.

### Does knock(1) collect any user data?

No, knock(1) is built with privacy in mind. It does not include any tracking, analytics SDKs, or send telemetry data. It only connects to the hosts you explicitly configure.

### What devices does knock(1) support?

knock(1) is currently supported on iPhone devices, offering a native look and feel with its clean SwiftUI interface.

### Is knock(1) free to use?

Yes, knock(1) is available for free. There are no in-app purchases or subscription fees associated with using this port-knocking client.

## Version history (last 2 releases)

### 1.1.0 — 2026-06-14

- New: Auto Knock sends selected sequences when you open knock(1) to save you taps.
- New: Optional iCloud Sync to back up and sync your saved sequences across your devices.

### 1.0.0 — 2026-04-21

No release notes.

## More apps by Jeffrey Cousens

- [NextEp - TV Tracker](https://appshunter.io/ios/app/nextep-tv-tracker/id6759259833)

All apps by Jeffrey Cousens: https://appshunter.io/developer/1877690927

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-08.*