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Flet'HFlet'H Docs

About OpenWrt

This documentation is still being edited and may differ from the actual version.

OpenWrt is an open-source operating system for routers and network devices. After installing OpenWrt, a router is no longer limited to the features exposed by the vendor firmware. You can install packages, adjust interfaces, configure firewalls, VPNs, IPv6, and IPv4 over IPv6 behavior.

Flet’H runs on OpenWrt and turns common Japanese DS-Lite, MAP-E, static IP, and independent IP setups into LuCI protocols and status pages.

Why use OpenWrt

Section titled “Why use OpenWrt”

More control
You can decide how interfaces, routes, firewall rules, DNS, VPNs, port forwarding, and IPv6 should behave.

Package-based extensions
OpenWrt can install features through apk or opkg. Flet’H is installed and upgraded as a package.

Good fit for complex lines
Japanese IPv4 over IPv6 services often involve DS-Lite, MAP-E, static IP, passthrough, and restricted port ranges. OpenWrt gives you a clearer place to configure these details.

Longer maintenance life
If your hardware remains supported, OpenWrt can often receive system and security updates longer than vendor firmware.

Learning curve

Section titled “Learning curve”

OpenWrt is not a consumer firmware you can always ignore after plugging it in. You should be comfortable with these tradeoffs:

  • Before flashing, you must match the router model, hardware revision, and firmware image.
  • A wrong network setting can temporarily disconnect the router and require recovery.
  • It helps to understand the basics of IPv6, line types, port ranges, and firewall rules.
  • Back up your configuration before system or package upgrades.

If you only want a router that works without touching network settings, OpenWrt may not be the easiest choice.
If you are willing to understand the configuration, it gives you more control and works well with tools like Flet’H.

Minimum skills

Section titled “Minimum skills”

Before configuring Flet’H, make sure you can:

  1. Log in to the LuCI web interface.
  2. Open Network -> Interfaces.
  3. Identify basic interfaces such as wan, wan6, and LAN.
  4. Check whether wan6 has an IPv6 address or prefix.
  5. Save and apply configuration changes.

After that, continue with the pre-install network check.