My linux box is RedHat with one NIC.
I did create 18 virtual interfaces from eth0:1 to ethO:18 in my machine.

I want to create routing between these interfaces, for instant i want to route packet from eth0:1 to eth0:5 via pass this packet through eth0:2 and eth0:3 before. (eth0:1->eth0:2->eth0:3->eth0:5) and vice versa.

But the problem is linux think that all of these 18 interfaces are in the same device. So, once i try to create the routing and send packet out,the packet will go directly from eth0:1 to eth0:5.

I try to create routing with iptables as well as using VLAN but it seem they didn't support virtual interface.

Do you guys have any idea how to make it comes true ?

that sounds like a pretty nasty mess... you sound like you're trying to do this without using formal vlans? it's possible to run multiple subnets on a single nic without VLAN's but it's a really bad idea, and should be avoiaded. running 18 of them is just daft... chekc the 8021q module and associated tools like vconfig to do this properly. http://www.linuxjournal.com/article/7268

Can some one please help me in setting up this ?

Regards,
Bala