Installing alternative third-party router firmware can significantly enhance the capacity and functionality of mid-range and budget class routers usually for free. Users should possess the necessary technical skills and feel comfortable flashing their router’s firmware with third-party firmware that may void the warranty of the router and could render the router inoperable if instructions are not followed carefully. Tread lightly and do your research ahead of time instead of after you’ve bricked your router.
Embedded Linux Firmware:
Ethernet Based Linux Router Embeded Systems Firmware using NetFilter and sometimes BusyBox and Network Time Protocol (NTP).
DD-WRT
https://dd-wrt.com/
https://en.wikipedia.org/wiki/DD-WRT
DD-WRT is a Linux based alternative OpenSource firmware suitable for a great variety of WLAN routers and embedded systems.
The graphical user interface is logically structured, and it is operated via a standard Web browser, so even non-technicians can configure the system in only a few simple steps.
https://wiki.dd-wrt.com/wiki/index.php/Supported_Devices
https://dd-wrt.com/support/router-database/
DD-WRT – Entware
https://github.com/Entware/Entware
https://github.com/Entware/Entware/wiki
Entware is a software repository for embedded devices like routers or network attached storages. It was founded as an alternative to very outdated Optware packages. Now x86, x64, MIPS, MIPSEL, ARMv5 and ARMv7 forks are merged into Entware.
https://wiki.dd-wrt.com/wiki/index.php/Installing_Entware
http://bin.entware.net/armv7sf-k3.2/Packages.html
Open-WRT
https://openwrt.org/
https://en.wikipedia.org/wiki/OpenWrt
OpenWrt is a highly extensible GNU/Linux distribution for embedded devices (typically wireless routers). OpenWrt provides a fully writable filesystem with package management and allows you to customize the device through the use of packages to suit any application. In practice, this means that you can have all the features you need with none of the bloat, powered by a Linux kernel that’s more recent than most other distributions.
Table of Hardware:
https://openwrt.org/toh/start
PC & Virtualization:
IP-COP
“IPCop – The Bad Packets Stop Here”
https://www.ipcop.org/
https://de.wikipedia.org/wiki/IPCop
The IPCop Firewall is a Linux firewall distribution. It is geared towards home and SOHO users. The IPCop web-interface is very user-friendly and makes usage easy.
Linux Components:
NetFilter
“Filter your Network Pipe above the Table”
https://www.netfilter.org/
https://en.wikipedia.org/wiki/Netfilter
The NetFilter project is a community-driven collaborative FOSS project that provides packet filtering software for the Linux 2.4.x and later kernel series. The netfilter project is commonly associated with iptables and its successor nftables.
https://www.netfilter.org/documentation/index.html
https://www.frozentux.net/iptables-tutorial/iptables-tutorial.html
https://ipset.netfilter.org/iptables.man.html
https://manpages.debian.org/unstable/iptables/iptables.8.en.html
https://www.unix.com/man-page/linux/8/iptables/
BusyBox
“The Swiss Army Knife of Embedded Linux”
https://www.busybox.net/
https://en.wikipedia.org/wiki/BusyBox
BusyBox is a software suite that provides several Unix utilities in a single executable file. It runs in a variety of POSIX environments such as Linux, Android, and FreeBSD, although many of the tools it provides are designed to work with interfaces provided by the Linux kernel. It was specifically created for embedded operating systems with very limited resources.
Command Help:
https://www.busybox.net/downloads/BusyBox.html
Network Time Protocol
“Time Synchronization over a Network”
https://www.ntp.org/
https://en.wikipedia.org/wiki/Network_Time_Protocol
The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks..
Deamon and Config File Help:
https://www.ntp.org/documentation/
https://manpages.debian.org/testing/ntp/ntpd.8.en.html
https://manpages.debian.org/testing/ntpsec/ntp.conf.5.en.html
Serial Ports:
Configure Cable Requirements for Cisco Console and AUX Ports
https://www.cisco.com/c/en/us/support/docs/routers/7000-series-routers/12223-14.html