3 nic's opensuse 11.4 with 2 isp's

Hello, i have my opensuse 11.4 with 3 Nic’s: for my lan ADSL1 ADSL2 not from the same provider. Unfortunately i am not a guru on networking and i am trying to setup in a way of wan failover as also round robin using the bandwith of two isp’s not adding them (10Mb +10Mb). Is there any way to do it? I do not have static public ip’s, the provider gives me dynamic ones. Please do not tell me to read the advance routing manual because it’s hard for me to understand. Is there any example to just follow and do the trick? Thank you all for your time!!

AFAIK there is no easy way to bond two ADSL connections without specialized hardware.

Be aware that

  • The simplest solution if the machine is physically accessible is to manually disconnect one patch cable and re-connect either NIC (only because you’re not using static IPs) to whichever ISP.
  • If you do configure both network connections as active at once and aren’t bonding the NICs to the same ISP, then you need to modify the route to one ISP with the highest priority and the route to the other with the lowest. That is because TCP/IP is a 2 way communication protocol and other machines need to communicate with the same interface (NIC) on your machine. If a response is instead sent to the other interface, that will be discarded (aka loss).

The second config above will support auto failover if the main connection fails completely, but note that if the connection is simply bad (even worse, intermittently bad) you can see that it’s still possible for packets to be incorrectly routed causing loss and problems.

Natch, if you support incoming connections you’re opening up a whole new set of issues related to auto (or manual) DNS record updating depending on which interface is active.

Bottom line, if you really want “intelligent” bonding and/or routing, ordinarily people spend the big money on appropriate devices.


don’t know if it help but here is some info i found with google:
DiegoLima.org » Iptables Load Balancing in a Nutshell
networking - Load balancing & NAT-ing multiple ISP connections on Linux - Server Fault