[RndTbl] Load-balancing / dual-WAN / multi-WAN routers or other solutions

Trevor Cordes trevor at tecnopolis.ca
Sun Mar 31 02:47:28 CDT 2013

On 2013-03-29 Hartmut W Sager wrote:
> Now THIS should get a discussion going.  What's the latest on
> load-balancing / dual-WAN / multi-WAN routers?  I only see two kinds
> - some very old D-Link (DI-LB604) and Cisco (RV042, RV082, RV016)
> models, and quite a few current models from completely unheard of
> Oriental companies.

I've done multi-homed Linux routers.  To do weird stuff without buying
major expensive gear (read: Cisco enterprise, Juniper, etc) your best
bet is to just do it in Linux (or BSD if you prefer, though I have no
experience there).

You can select what traffic should go out what modem (by nearly any
criteria since it is iptables based).  I usually select it based on
port (put VNC, ssh over low-latency pipes) or intranet IP (give certain
machines fast / slow internet).  Return packets come in the same modem
as the outgoing.

I haven't yet done automatic failover but it should be fairly easy to
write a script to detect pipe failure and tweak iptables to direct all
traffic out just one pipe.

Your friends here are:

ip rule ... table
ip route ... table
echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter
iptables -t mangle
(and maybe more I'm forgetting, this is from memory at the moment!)

and you can do QoS fairly easily at the same time.

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