is it OK to apply tc htb rate limiting to the tunX adapters?

psycroptic · 01-19-2014, 12:43 AM

to throttle openvpn's traffic over tun0? could this cause problems? or would this be a better question asked to the openvpn folks?

baldy3105 · 01-19-2014, 12:19 PM

I don't see why not. tc should operate on a tunnel interface like any other. There may be a minimum bandwidth under which openvpn starts to get upset but how low are you talking about?

psycroptic · 01-19-2014, 01:45 PM

around 10mbit

baldy3105 · 01-20-2014, 01:12 PM

OK I was thinking about KB's! I can't imagine why that should cause a problem. Tc HTB is not like policing which simply discards excess traffic, HTB buffers throttled traffic in the same way that would occur of you set a physical interface to 10MBps. So while I've never done it, the only reason it might cause a problem is if your average offered VPN traffic rate is higher than this, then you'll hit congestion issue similar to running the physical at 10M.

psycroptic · 01-20-2014, 02:43 PM

trying it, seems to work fine. thanks.

one other separate thing, is there a difference between classifying traffic using "tc filter" and "iptables <filter rules> -j CLASSIFY --set-class x:y"?

baldy3105 · 01-23-2014, 01:31 PM

Not that I'm aware of but I'm not that hot on iptables, I've spent much more time on tc. You can do a lot more manipulation with iptables so I assume you can classify it there so you can do some tinkering with the traffic before passing it onto tc.