Constructing a Linux-Based Network Testing System?

10Brett-T asks: "Is it possible to build a Linux box with two interfaces to test a network's ability to carry traffic between two ports? I work for a company developing ethernet switching hardware. We need to test its ability to carry traffic correctly under a variety of conditions. Various vendors have expensive test platforms available that may or may not do the tests we want, but we have a tight budget. We decided to try building a Linux system with two ethernet interfaces, and modify the routes to force the traffic to go across the network. Testing would be as simple as running an FTP connection between a client on one interface and a server on the other. This would be a great victory for Linux in our company, if I could get it working. The problem is that I cannot figure out how to bypass the Linux kernel's TCP/IP stack routing optimization. All the combinations of routing table modifications and iptables that I've tried still don't make the packets flow out the interfaces and on the wire instead of within the stack. Has anyone else tried something like this before? How did/would you approach this?"

Comments

Use two machines?

[ZeroLogic]

Wouldn't the easy solution be to use two machines instead of one? Am I missing something?

/ZL

Two machines?

[ObviousGuy]

You want to send packets from one NIC and catch them on another? Why not use two machines?