Say if you have 3-4 cache servers that need to talk to one another, rather than having to give it a public IP (even though it's not routed outside of DO), you c

Say if you have 3-4 cache servers that need to talk to one another, rather than having to give it a public IP (even though it's not routed outside of DO), you can give it an internal IP so all traffic is routed through that network interface instead of the public one - slightly better for security though not perfect as everyone with a DO box can see your private network ip, so you still need to secure it.......