Fair NAT 0.80

Fair NAT is a script for configuring NAT on dedicated Linux routers. This is the home of my linux router shaper script which allows something like fair bandwidth sharing among clients in the local network. The script is not great or anything - please dont expect the holy grail here - I just thought Id publish it because many people helped me write it and maybe someone has some use for it. I bet there are still lots of things that can be improved. Sorry about the crappy design of this page, I dont have time to put more effort in better looks. You have a certain number of Clients (User A - User N) in your LAN which are connected by a Switch (or a Hub or BNC) to the Linux Router which is supposed to act as a gateway to the internet. The trouble now is, User B has a lot of downloads running and User C uploads stuff day and night, which leaves User A who only wants to use an interactive SSH shell in the rain, since B and C already use up all bandwidth the internet connection offers. What we need to do is to share available bandwidth fairly among clients. In order to achieve this, I first tried several searches at Google and Freshmeat. This turned up quite a lot of results, like the Linux Advanced Routing & Traffic Control HOWTO which is a must-read and also contains great scripts, like the Wondershaper for single users. Another great general purpose script I found was HTB.init, which doesnt do anything by default, but gives you an easy way to setup HTB queues. In case you prefer CBQ, theres a CBQ.init too. If you dont know what Im talking about, read the HOWTO above or continue reading here. Since I never found a script that did exactly what I wanted, I decided to write my own. Its designed to be an all-I-need script, therefore it does not just setup Traffic Shaping, but Masquerading and Port Forwarding too. In short, it does everything that has to do with IPTables and Traffic Control. I use HTB (Hierarchical Token Bucket) to share bandwidth among clients (one class per client). On top of that I added a PRIO queue to prioritize interactive traffic on a per-user basis. On top of PRIO I set SFQ to treat connections fairly. In version 0.72, experimental support for IPP2P to recognize peer-to-peer traffic was added. This is the simplified scheme for routing: HTB class (for bandwidth sharing) | -- PRIO (for prioritizing interactive traffic) | --- Interactive: SFQ (to treat concurrent connections fairly) --- Normal: SFQ --- High-Traffic: SFQ [ --- P2P: SFQ (if IPP2P support is enabled only) ] I bet this can still be improved and Im always interested in ways to do so. In case you want another class structure, this can be done by replacing the parent_class and user_class functions in the script. See CLASS_MODE in Configuration section and the function documentation in the script for details. Feel free to send me your own functions with a short explanation, if you want me to make them available for everybody. Heres a "real" graphic, which shows the complete qdisc/class structure on $DEV_LAN if you use the unmodified example configuration file. This graphic was created using a hacked version of Stef Coenes show.pl script and GraphViz. Click here to see it, but I warn you: its quite big. Heres a similar picture, which includes IPP2P support. Note that there are more filter rules (the blue arrows) now which put the filesharing traffic into the users prio band 4.. Fair NAT is a Linux Router QoS/Traffic Shaping script for fair bandwidth sharing among clients in the local network.

Requirements:	No special requirements
Platforms:	Linux
Keyword:	Allow Fair Nat,  Class,  Fair,  Fair Nat,  Linux,  Nat,  Networking,  Script,  Sfq,  System,  Tos,  Traffic,  User
Users rating:	0/10