On Thu, Feb 28, 2002 at 11:24:34AM -0600, Steve Westerhouse wrote: > > On Thu, Feb 28, 2002 at 10:33:57AM -0600, Steve Westerhouse wrote: > > > I have two DSL modems (each has same bandwidth) connected to my > > > RedHat 7.1 Linux gateway. There are 3 NICs in the system (1 LAN, 2 > > > WAN). How can I combine the bandwidth of both of these modems? I > > > have a feeling this can be accomplished using iptables in some > > > way. I understand that any given file transfer will not be able to > > > exceed the bandwidth of an individual DSL modem. The real > > > advantage comes in when there are > 1 concurrent connections. > > > > What kind of things are you looking to load balance? You have to be > > aware that most things could break if you suddenly come from a different > > IP in the middle of a session. For example you're playing Quake and > > suddenly your IP switches or half your packets are coming from a > > different IP. > > > > I would look into different proxy servers to do this job for you. Looking > > over the Squid pages you can probably do something with parents/siblings > > and routing those over different links. > Thanks for your reply. > > I am aware that spreading packets across two ips could mess things up but > I'd expect that the Linux gateway would avoid this. My expectations are > that the gateway would keep track of bandwidth in use on both pipes and > whichever one had the smallest utilization would be chosen for the next > transfer. This would have to use connection tracking to work properly. I > don't think it would matter for UDP based apps but I suppose it's really up > to the app.
How does iptables know what the "next transfer" is? If you're pulling down a web page each grabbing of an image looks like a new transfer, there is no easily seen (to iptables) glue that connects them together. It might matter to a website who is connecting to it. I think you would have to do this on an application by application basis. Is there a particular one you had in mind? An FTP proxy that initiated new connections over different links would be very handy especially when pulling down multiple RPMs that you need to upgrade KDE for example. Chris
