Gernot Walzl

OpenWrt

I use OpenWrt because my network at home is my privacy.

Contents

Prerequisites

Installation

  1. Download the OpenWrt firmware for your router:
    https://openwrt.org/toh/views/toh_fwdownload
    If the firmware of the original vendor is installed on the router,
    the column "Firmware OpenWrt Install URL" shows the required firmware.
  2. Flash the firmware:
    Open the web interface of your router (usually http://192.168.1.1/)
    and select the previously downloaded firmware for installation.
    The installation takes a few minutes.
  3. Set a password:
    Open the web interface of your newly installed firmware (http://192.168.1.1/).
    The option Administration under System allows you to set a router password.
    If a password is set, login via SSH is possible.

Configuration

The web interface LuCI is used to configure OpenWrt.
Configuration files are stored in the directory /etc/config/.
These files can also be edited with an editor over SSH.

Internet Access

Select Interfaces under Network to edit the WAN interface.

Protocols like PPPoE (for VDSL) or DHCP work out of the box.
Support for other protocols can be added by installing additional packages.

To use a custom DNS server (like Google Public DNS) for name resolution,
edit /etc/config/network: 

config interface 'wan'
    #...
    option peerdns '0'
    option dns '8.8.8.8'

System Properties

Select System to set the local time and the timezone of the system.

Wireless Access Point

On a fresh installation of OpenWrt, the wireless access point is disabled.

Select Wireless under Network to setup the SSID,
configure the encryption and enable the access point.

Package Management

Additional software can be installed using the web interface or
using the command line via SSH.

The web interface LuCI provides a convenient way of managing software packages.
Select Software under System to install additional packages.
Click Update lists... to update the list of available packages.

The command line tool opkg is used as package manager.
opkg install <pkg> installs a package.
opkg update updates the list of available packages.

Dynamic DNS

Packages

Firewall

To allow SSH access from the WAN interface, the firewall needs to be configured.

Packages

Configuration

Select Firewall under Network to add a custom rule.
Custom firewall rules are stored in /etc/firewall.user: 

iptables -A input_wan_rule -p tcp --dport 22 -m conntrack --ctstate NEW \
    -m recent --set --name SSH
iptables -A input_wan_rule -p tcp --dport 22 -m conntrack --ctstate NEW \
    -m recent --update --seconds 60 --hitcount 8 --rttl --name SSH -j DROP
iptables -A input_wan_rule -p tcp --dport 22 -j ACCEPT

Wake on LAN

Packages

Hardware

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