2 inet connections

[Claudiu Dragalina-Paraipan]

Hi,

I have this situation: 2 inet connection at 2 different ISP, one with 
2Mbps and one with 128kbps; and a big NATed network behind it, and a 
small group of real addresses.
I want to do this: use the first connection as "primary" connection, and 
if this fails, go to the second connection, as a backup.
The problem is that none of the ISP will help me in any way, so I have 
to find a solution by my own.

I am trying to avoid the making of a software that watches the 
connections and "declare" a line dead when no TCP connection can be 
made, thus switching to the secondary/backup line.
I realize that there is no way of using the group of real addresses on 
the backup line, since they are not routed, but this is not of such 
importance. I need only to provide Internet connection for the NATed 
network.

So... can someone provide me with some good practical advice for this 
situation ?

NOTE:
I want to use FreeBSD for this, so FreeBSD specific advices are welcome. 
In fact I don't even think of other solution.

I realize that this is not a very common situation, and I hope I have 
explained it sufficiently clear.

Thank you very much.

Best regards,


-- 
Claudiu Dragalina-Paraipan
e-mail: dr.clau at rdslink.ro