Routing question -- multiple gateway setup?

[James Knott]

Robert Brockway wrote:
> On Sun, 22 Aug 2004, James Knott wrote:
> 
> 
>>Are your links with the same ISP?  I thought load balancing had to be
>>configured at both ends.
> 
> 
> Depends on how the load balancing is done.  With MLPPP both physical links
> appear to be one logical link so support is needed at both ends, but with
> iproute2 the packets are sent out one link and then the other in turn.
> 
> It would be like you were sitting there and toggling the default route
> really fast.
> 
> Iproute2 actually allows for weighting so you could send packets out 2:1
> in favour of a faster link for example.
> 
> As mentioned, when this is done on the same box as NAT (last time I
> checked) it falls flat.  The kernel doesn't seem to be able to conn_track
> them properly and as a result it drops some returning packets in this
> situation :(

Given that you've got more than one connection, you'll have more than 
one IP address.  This means that the out going packets will have 
different addresses, which will mean they can't be part of the TCP 
connection.  Also, with the two routes, how are the packets returning to 
you, forwarded to the correct interface?
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