In linux, there is a kernel module called "dummy", which allows you to generate dummy network interfaces such as "dummy0", "dummy1", etc.
1. sudo modprobe dummy numdummies=2
2. now you can do "ifconfig dummy0 192.168.1.124" to give it an IP address.
3. you can also rename the dummy interface with the following command:
ip link set dummy0 name eth3
you need to "down" the interface before running the command above.
With the combination of dummy interfaces and ability to rename dummy interfaces, you can do a lot of fun things with them.