I just transitioned my home server from and older desktop with two LAN ports (Server B) to a new low-power one (Server C) with only a single LAN. I get three IP addresses from my ISP and me and my room mate shared them like this:
External Network: 18.104.22.168/16 Internal Network: 10.0.0.0/24 Coaxial---[Modem]---[10/100 Switch] | | \------Server B eth0 (External IP #1) | \----------Desktop A eth0 (External IP #2) \-------------[E3000 Router] (External IP #3) | | \--------Server B eth1 (Internal IP) | \----------Desktop B eth0 (Internal IP) \------------Other Stuff (Internal IPs)
Server B eth0 gets replaced with Server C eth0.
--Router A - Cisco E300
--Desktop A - Not important
--Server A - Not important
--Desktop B - 1 Ethernet, plenty of PCI-E, high power consumption
--Server B - 2 Ethernet, moderate power consumption, replaced with Server C
--Server C - 1 Ethernet, No PCI-E, low power consumption
--Switch - Layer 2
In my old setup (above) I routed all outbound traffic from my server (B) out of the external interface (eth0). However, incoming connections from the internal interface (eth1) would also exit that interface. By this method I could have a Samba share with all my media on my server (B), but keep torrent traffic off the broadcast domain of the other equipment.
In my new setup, the lower-power server (C) only has one LAN port (eth0) and no internal expansion (USB 2/3 is available, but no PCI[-E]). Is there a way I can continue to have my Samba share, but without the server's internal interface? Is there a cheap and reliable way to add another LAN interface?
Edit: Cisco Router is a consumer model, and is not flashed with DD-WRT or likewise because it is my room mates. I have an older WRT54G with DD-WRT at my disposal if needed. (it is a bit flaky) The switch is a Layer 2 switch with no administrative interface
Edit: The server needs to be external to the E3000 router as my room mate has a habit of deleting the port-forwarding settings on the E3000.