Because of my poor english,my answer may have some fault.
See your modem,then it may have RJ-45port,then you have no need of complex design.
ISP's comment means
"Between two connection ISP's side endpoint ip is 245 and your side is 246."
One example,below command may not exactly I'm not linux user.
Eth0 : 246/30 =>can't use any other IP
eth1 : 249/29 =>can use 249~254
eth2 : 192.168.1.1/24
route add -net 220.127.116.11 netmask 255.255.255.248 eth1
route add -net 192.168.1.0 netmask 255.255.255.0 eth2
route add default gw 18.104.22.168
You can connect two switching hubs each eth1 and eth2
There may be some other net design,but if you need to use public clients & private clients,then seperate interface using will remove much more complex.
This style design may need some considerance about BUS I/O and inturrept mechanism.
콩글리쉬로 할려니 죽겠네::
this is Korean Alphabet.English is very hard;;;
Last edited by ggeagle; 06-23-2010 at 12:44 PM.