Linksys uses fast-nat since they don't offer all features dd-wrt offers. In Linux, there are actually two separate types of NAT that can be used, either Fast-NAT or Netfilter-NAT. Fast-NAT is implemented inside the IP routing code of the Linux kernel, while Netfilter-NAT is also implemented in the Linux kernel, but inside the netfilter code.
Changing NAT Type By Forwarding Ports on DD-WRT Router Jun 09, 2015 Create a NAS with a DD-WRT | Step by Step guide Jun 29, 2018 Adventures with DD-WRT Part 6: UPnP and NAT-PMP Adventures with DD-WRT Part 6: UPnP and NAT-PMP. DD-WRT ships with a UPnP implementation built-in. However, according to multiple posts I've found, the implementation seems to be kind of broken. There are a sufficient number of applications that fail to operate with DD-WRT's chosen UPnP daemon that many users in the community have worked around it.
AUSTIN, TX – June 2, 2015 – Buffalo Americas, a leading provider of external storage, network attached storage (NAS) and networking solutions, today announced the availability of its new wireless dual-band gigabit router series. This series introduces the market's first routers pre-installed with the latest open source router technology—DD-WRT NXT firmware.
Linksys uses fast-nat since they don't offer all features dd-wrt offers. In Linux, there are actually two separate types of NAT that can be used, either Fast-NAT or Netfilter-NAT. Fast-NAT is implemented inside the IP routing code of the Linux kernel, while Netfilter-NAT is also implemented in the Linux kernel, but inside the netfilter code. DD-WRT and IPTABLES - Networking | DSLReports Forums
DD-WRT setup with NordVPN | NordVPN Customer Support
DD-WRT About. DD-WRT is a Linux based alternative OpenSource firmware suitable for a great variety of WLAN routers and embedded systems. The main emphasis lies on providing the easiest possible handling while at the same time supporting a great number of functionalities within the framework of the respective hardware platform used.