Re: Fun with routes

[Rich Puhek <rpuhek@etnsystems.com>]

aCaB wrote:

> I was trying to figure out a cheap solution to increase upload speed for
> one of my customers (currently using ADSL).
>
> I soon realized that dedicated lines such as CDN, HDSL etc are too
> expensive in respect to common ADSL and come up with a brain-dead idea
> of bounding various ADSL lines together...
>
> Let's say I have ISP-A and ISP-B providing me 2 lines with static
> addresses IP-A and IP-B; both ISP's allows source address spoofing.
> For simplicity let's also say I will only accept incoming connections on 
> IP-A, but, to increase upload speed, I want reply packets to come out 
> both from ISP-A (with no modifications) AND ISP-B (with source address
> spoofing).
>
> I'm quite sure this can be done, but I'm not sure if iproute2 would do
> this.
>
> Any ideas?
>
> I'm aware of legal concerns regarding IP spoofing, so that this idea is
> quite unlikely to become a real life example, but I'd still like to know
> about it for my own curiosity's sake.
>
> Thanks a lot.

First off, ISP-B should be dropping your spoofed packets on the floor 
once they hit their network. Your example does specify that this is not 
the case, though.

Load balancing the two will become a problem... how does your computer 
decide which path to send on? Aside from a few specific cases (like 
equal-cost load balancing) your routing protocol/procedure/program 
should make the same decision every time for where a packet should be 
routed.

A much easier way to do this, using existing proven technology would be 
MLPPP to one provider (assuming that your provider supports MLPPP and 
that you can get client hardware to do so as well). Some careful routing 
with two separate DSL connections to the same provider will work as well.

--Rich