Want the short version? Skip to TLDR. (Too Long, Didn't Read)
Sabai Technology began with loading scripts into open source router firmware that automated setting up VPN clients. At first this was DD-WRT, and it eventually expanded to Tomato and, to a lesser degree, OpenWRT. However, the purpose of Sabai has always been to make VPN setup easier, and the process of loading scripts into router configurations was slow, kludgy, and error-prone. So, while it automated the process, it was only half of a solution.
Sabai OS began with modifications to Tomato to integrate the automated VPN setup so that the user no longer had to manually enter scripts or other configuration information. Before its first release, it progressed to a point where a user only had to supply either their PPTP/L2TP credentials for login, or upload a complete OpenVPN configuration. Over time this was refined to provide increased functionality, including supporting OpenVPN usernames and passwords (which previously had to be entered on the command line when OpenVPN started). Thus debuted Sabai Technology’s firmware for its VPN Router.
Policy routing has always been a bit of a white elephant of networking. Often it requires an enterprise class hardware setup and extensive configuration to shake out bugs. However, a subset of policy routing based on the origin of traffic is easier to automate and very useful for VPN applications.
For instance, suppose you have both a set of devices at home that are personal and use lots of bandwidth and also a few devices for work which need to connect to your work intranet. Typically, one would have to configure a VPN client on all of those work devices to allow them to operate on your work's intranet. However, with Gateways, the router can be configured to run this VPN, and all devices on the network can by default have their traffic routed out through your normal network connection. The work devices can be specifically selected to be the only devices that route through your VPN.
Gateways allows individual devices to be routed according to the user's wish.
The VPN Accelerator
Originally, the router-based VPN client was not amazingly fast. The MIPS CPUs of common routers were not especially powerful, and also did not have special instruction sets dedicated to encryption like common desktop CPUs of the time. Since then, ARM routers that are more powerful and also have special instruction sets have become common in home routers.
However, even compared to those, the VPN Accelerator performs considerably faster. It is a dedicated computer that runs the VPN client for a Sabai OS Router, and Gateways makes it possible to route traffic through the VPN Accelerator.
Sabai Home Server
Until recently, Sabai OS and its related products were geared towards VPN clients. There is a good reason for this: many VPN applications users want demand bandwidth (such as video streaming), and Sabai products have been made to make those specific applications easier to use. However, one major application for VPN technology is accessing a remote network as if one were local to it, just as in the work VPN example above.
What if you were not home wanting to access a network outside of your house, but instead outside of your home wanting to access its network? This is the capability that the Home Server supplies. It allows you to log into your home network from anywhere you can use a VPN client, and it does so securely. Further, the Gateways feature of your home router's Sabai OS allows you to select how traffic coming from your Home Server is routed, and the same feature on your remote Sabai OS Router allows you to select which devices to route to your home network.
Because most home internet has limited upload speed--the speed which is your connection speed as a remote client--the Home Server is not recommended as a replacement for VPN services; rather, it securely connects you to home, which a VPN service generally cannot. Users with a good home upload speed may find streaming from their home network works well, though.
How Does Sabai OS Compare
Toe to toe with other router firmware, Sabai OS puts VPN first.
For this reason, there are some features that it specifically does not offer because they either interfere with the VPN or increase the complexity of user configuration with little to no benefit. TOR, BitTorrent clients, and sophisticated web servers are a few such elements Sabai OS does not include. Additionally, a wide set of rarely used networking configurations which are known to cause significant and difficult-to-trace bugs have been either restricted or removed. This is all to make it easier for the user to set up what they want without getting side effects that might be unexpected or even baffling.
Sabai OS adds many benefits.
VPN client setup is so seamless it's sometimes hard to imagine how tedious and error-prone setup in OEM and other FOSS firmware can be. For many other router firmwares, setting up OpenVPN requires a long list of configuration entries, as well as comparing OpenVPN versions and hoping the latest build of your chosen firmware supports your provider's features. Sabai OS uses the latest release of OpenVPN as of its release version (ie, Sabai OS released in June 2017 would use the latest OpenVPN release available at that time), and adds some features not available in mainline OpenVPN releases, such as the XOR/Scramble option and selective DNS. Sabai OS also adjusts OpenVPN configuration files to account for known issues in supplied VPN configurations.
Selective routing with Gateways and greater speeds with the VPN Accelerator are out of the box solutions with Sabai OS, whereas other firmware requires extensive special networking configuration for either of these. Port forwarding works with both the VPN and the normal internet connection (WAN), and Sabai OS allows the user to select either or both for forwarded ports. This would have to be manually configured on other firmware, if it's even possible.
Additionally, Sabai Technology provides extensive support; such support is often lacking or nonexistent for other firmware options. Often the only recourse one has to diagnose a problem or set up some new special service is to search online and post in forums hoping for some knowledgeable response. By contrast, users can contact Sabai by email anytime (firstname.lastname@example.org), and users also have the option of scheduling support sessions with our team.
Sabai already takes the worry out of flashing your router with non-OEM firmware, but also adds the availability of the Accelerator for speed and the option to maximize the utility of the Home Server. Sabai OS aims to be the best firmware for a VPN Router.
From Now To The Future
Sabai OS has recently added VPN-supplied DNS and local DNS Blocking capabilities, which are also coming to the VPN Accelerator. Further features for controlling the VPN and giving these devices a unified interface are on the way. Seamless networking between local and remote devices is Sabai's goal for 2020.
The Ideal Sabai Setup (2019 Edition)
At home, your Sabai OS Router runs your work intranet VPN for those devices; it also routes your Home Server traffic normally, while routing your Home Server devices according to your choices (some of these client devices might be work-related and route through that VPN). In your home away from home, be that a hotel, expatriate residence, or even a mobile setup, your remote Sabai OS Router runs a VPN to your Home Server. Also, your VPN Accelerator runs your VPN Provider. This allows you to select between streaming over the Accelerator, checking your home IP cameras or adjusting your smart thermostat through the Home Server, or even connecting to your work VPN remotely just by changing your Gateways settings.
TLDR - Too long; Didn't Read
Sabai OS VPN Router firmware makes it easier to use VPNs and VPN-related services, including the VPN Accelerator and Sabai Home Server; Sabai Technology provides world class customer service and technical support to help guarantee its ease of use.