DNS Server on eth0 & eth1

[kilburn]

The ability to configure FTP and DNS services is part of ispcp features, whereas the ability to configure fancy routing schemes isn't. That's how it's different...

BTW, you should first setup a "split access" network as explained in the Linux Advanced Routing and Traffic Control (LARTC) manual. Then, install ispcp as usual, specifying the IP from router1. Finally, manually modify the bind templates (/etc/ispcp/bind/parts) so that the IP used there as NS is the one from Router2.

After all this, clients should come in through Router1, so your server will answer through this route (as explained in LARTC). In contrast, DNS requests will come in through Router2, and therefore answered through it accordingly.