On Mon, Mar 01, 2004 at 02:08:43PM +0000, Craig Tinson wrote: > I was just having a thought... and wondered if anyone had any pointers > or even know if this is possible.. > > I have a 1Mb cable connection.. and am getting a 2Mb DSL line installed > in a couple of days.. > > I was wondering if I can use both connections... from one gateway > machine.. and combine them.. effectively have a 3Mb connection.. They will live in different IP subnets, so you will have to direct individual flows to a particular ISP. The canonical starting point is here: http://www.lartc.org/lartc.html#LARTC.RPDB.MULTIPLE-LINKS The above section describes a basic configuration and links to Julian Anastasov's routing patches found here: http://www.ssi.bg/~ja/#routes Those patches are used to extend the kernel routing functionality for simpler (static) configuration and robustness. The patches prevent certain routes from being flushed when an interface goes down, and improves detection for dead gateways (i.e., your cable modem and ASDL router). On Julian's pages you will find Christoph Simon's Nano-Howto: http://www.ssi.bg/~ja/nano.txt There is a pre-packaged version of Christoph Simom's solution available under the GPL from: http://skypipes.com/ If you are patching your kernel, you may also want to add some functionality such as connection marking (CONNMARK) from Netfilter patch-o-matic: http://www.netfilter.org/ Beware that applying some of the patches requires that you also rebuild iptables against updated kernel headers. E.g., if you install the kernel source in /usr/src/linux-2.4, then you can install the iptables SRPM and change KERNEL_DIR=/usr to KERNEL_DIR=/usr/src/linux-2.4 in the spec file before rebuilding: perl -pi.orig -e 's!KERNEL_DIR=/usr!$&/src/linux-2.4!g' iptables.spec Change the release number in the spec file and build, rpmbuild -ba iptables.spec Additional documentation on Linux policy routing can be found here: http://www.policyrouting.org/ On final cautionary note: you may encounter session-oriented services and protocols that will examine your IP address. In that case, all traffic for that session (which may consist of multiple TCP connections) needs to go through the same ISP, so that the connections originate from the same external IP address. One can address this with policy routing rules, netfilter, or a combination of both. Regards, Bill Rugolsky
