I am pretty sure I know the answer to this, but 2 technical people in my organization cannot agree, so I'm putting this on ServerFault to get a final opinion.

We have a relatively simple set up in a data center:

  • About 6 servers connected to an unmanaged Dell switch providing various web services.
  • The Dell switch has the plug from our network provider.

We want to do file transfers between 2 servers to keep them in sync. Each server has an external IP and an internal one (ex:

Is there an advantage to connecting the 2 servers doing the transfers using the internal IPs rather than the external ones?

  • 2
    Are the external and internal networks both handled by the same switch, or do the servers have different network interfaces for internal than they have for external? – Shane Madden Aug 14 '11 at 7:50
  • Answering a question with a question: where is your firewalling/routing/NATing taking place and what is the speed of those interfaces? You could get yourself into a situation when you end up with your traffic for external IPs running through a NAT device with 100 MB interfaces and your machines are connected to the switch with 1000 MB interfaces. That would alter your speed dramatically. – Keith Stokes Aug 14 '11 at 11:58
  • Hi guys- Our switch is connected to a router which belongs to our colo provider. I do believe it is 1 GBit, but it's unclear. Also, I'm sure there's tons of clients plugged into that router. How does that affect things? – Jay Aug 15 '11 at 15:11

From a network performance standpoint, if the public IP addresses are also on the same LAN as with the private address configuration (where all the systems are on the same subnet configuration(s)), then they are functionally equal in network routing/transport.

One slight advantage on the private IP plan side would be layer 3 separation from others "snooping" at layer 3, but that does not necessarily provide any protection at layer 2 (if it is compromised).

| improve this answer | |

About 6 servers connected to an unmanaged Dell switch

Assuming both IPs are on the same interface, or they are on different interfaces, that connect to the same unmanaged switch, then there really is no difference.

I would be slightly concerned that there is no firewall/edge device between your systems and the network provider.

| improve this answer | |
  • What do you mean by interface? You mean NIC card interface? They are separate PCs with separate network cards. The external IP address range is x.y.z.226 - x.y.z.254, subnet mask Seeing as we do not have an edge device at this time (and won't for the next little while), what do you recommend in terms of external vs interal IPs? – Jay Aug 15 '11 at 15:18

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.