[c-nsp] Fwd: Load Balancing two different ISP's

[Ted Mittelstaedt]

----- Original Message ----- 
From: "chip" <chip.gwyn at gmail.com>
To: <cisco-nsp at puck.nether.net>
Sent: Thursday, September 14, 2006 5:25 PM
Subject: [c-nsp] Fwd: Load Balancing two different ISP's


> On 9/14/06, Paul Stewart <pstewart at nexicomgroup.net> wrote:
> > If a customer has a 1800 series router for example with two "outside"
> > ethernet ports.... And two completely different ISP's on those ports -
> > what's the best way to load balance traffic for redundancy and load
> > sharing purposes??
> >
> > We'll presume that the customer is running NAT of course....
> >
> > Thanks,
> >
> > Paul
> >
> >
> > _______________________________________________
> > cisco-nsp mailing list  cisco-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > archive at http://puck.nether.net/pipermail/cisco-nsp/
> >
> 
> Outgoing, from the 1800, 2 static routes should do the trick.  Just
> make sure that they include the interface.
> ip route 0.0.0.0 0.0.0.0 fe1/0 isp1.nexthop.ip
> ip route 0.0.0.0 0.0.0.0 fe2/0 isp2.nexthop.ip
> 


That is rediculous and I'm still amazed to see this kind of stuff in
a forum where people should know better.

Your sourcing packets with an IP address assigned from
ISP #1, out the interface to ISP#2.  Whereupon they will
get 1 hop then be killed by ISP #2's anti-spoof filter.

> Incoming...well that's gonna be a little different and going to be
> tough to get evened out if even possible.
> 

The only way to load balance with 2 different ISP's is to obtain
your own AS number and run BGP to each ISP and then
advertise a block of numbers.  The smallest advertisement
that any BGP upstream is going to take will be a /24

Ted