Loading balancing with more than one ISP.

[Chris Knipe]

> On Sunday 18 January 2004 06:10, Dinesh Nair wrote:
> > what i do today is i set the default route to the ISP i am more convinced
> > off, with static routes of certain large CIDR address blocks going out to
> > the other ISP. i decided on those large blocks after checking the global
> > route tables, AS PATH diagrams and experience of link quality. you can do
> > this by using tools such as the Looking Glass servers, RouteViews.Org and
> > even Netlantis.org for your situation. i'm not running routed,
> > zebra/bgpd/ospfd on this at all, since it's all static routes and i can't
> > find an ISP ospf/bgp router willing to exchange routes with me.
> 
> Same for me...
> Anyway, thanks for the explanation :)
> I really appreciated.
> 
> Antoine


Yes, here as well.  However, this brings (to me at least) a very big problem.

I route network A over gateway A, and network C over gateway B. (say, 2 x /12s)

I have a service set up, some.host IN A A.A.A.x (i.e. in network A and gateway
A).  Now, the moment some one from network B connects to the service I've setup
on network A, the FreeBSD Box will route the reply packets out on network B 
(because of the client's address) and hence, it follows a invalid networ path
and the connection fails.  The same will also happen when someone from Network A
tries to connect to a IP on Network B.... ex:

-- 192.168.1.0/24 --- | BSD ROUTER | --- 10.255.255.0/24 ---
                          - Some Service on here
                          - 192.168.1.0/24 routed to sis0
                          - 10.255.255.0/24 routed to sis1


The moment 192.168.1.x tries to connect to my IP address(es) from
10.255.255.0/25, the connection fails - and vica versa.

If I can manage to solve this, then I'll be a *VERY* happy chappy.  But other than
that, as mentioned previously, the ipfw fwd thing doesn't work for me either - it
forwards the packet to a port (won't really help forwarding ftp packets to port 21
of your router now, would it).  So yes, I'm also stuck with this - and the sad part
is I'll more than likely be adding a 3rd gateway to my network pretty soon....

Regards,
Chris.