Re: Routing over multiple interfaces

[Arnd Hannemann <arnd@arndnet.de>]

Am 01.11.2010 22:16, schrieb David Miller:
> From: David Woodhouse <dwmw2@infradead.org>
> Date: Mon, 01 Nov 2010 17:12:02 -0400
> 
>> But when I do a large upload, I find that the kernel is only ever using
>> a *single* link at a time, rather than both. How can I make it use
>> *both* links? It's fine to confine each flow to a single link if it
>> doesn't saturate that link... but once the queue is full, it should
>> overflow onto the other device.
> 
> Once a TCP socket gets a routing cache entry, that's what it uses
> for the rest of the life of the connection.
> 
> The multi-pathing decision happens at the time the routing
> cache entry is created.

You should be able to come a solution with netfilter (probably not so efficient):

iptables -t mangle -A PREROUTING -d $EXTERNAL -m statistic --mode nth --every 2 -j MARK --set-mark 6
ip rule add fwmark 6 table ppp1
ip route replace $EXTERNAL via $PPP0GW
ip route replace $EXTERNAL via $PPP1GW table ppp1

Regards,
Arnd