[Gllug] networking guide

[Nix]

On 30 May 2007, Tethys outgrape:
> Nix writes:
>
>>> I am specifically interested in brushing up on my routing knowledge in
>>> Linux - am looking at aggregating a network connection over two DSL
>>> uplinks.
>>
>>You can't do that sort of thing with ifconfig/route: look at
>><http://lartc.org/> and get ready to ip(8).
>
> Even with ip, it's going to be *very* difficult to do, as you'll have
> two different source addresses, one for each DSL line.

That's no problem:

ip route add 192.168.14.160 proto static src 192.168.14.159 dev adsl

et seq. You don't even need more than one routing table (at least, not
necessarily, although if you're planning to play complicated shaping
tricks with the data going out of one or the other pipe you might find
that useful).

>                                                        Sure, you could
> NAT one to the other,

No need.

>                                     And even if you get past that, you're
> likely to run into firewall problems due to the asymmetric routing that
> you've created.

Um, ipchains knows about this stuff. ipchains is after all only an
interface to the netfilter subsystem, which is invoked *by* the very
network layer that's doing all these elaborate routing tricks.

> Rather than true load balancing across the two lines, the best workaround
> is probably policy based routing -- i.e., send all web traffic over one
> line, and ssh traffic over the other, for example.

Um, wasn't that what you were just arguing against?

-- 
`On a scale of one to ten of usefulness, BBC BASIC was several points ahead
 of the competition, scoring a relatively respectable zero.' --- Peter Corlett
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