Tyler
When you say external IPs do you mean public IP addressing. And do you mean you are breaking the /24 down so you can use /30s per server ? If so be aware you are wasting a lot of useable addresses by doing this.
To do it on the 3750 you could do one of 2 things per server -
1) create a L2 vlan. Create a L3 SVI for that vlan and assign it an IP from a /30. Then use the other IP for the server and allocate the port the server connects to into the vlan.
or
2) if it is only going to be a single server you could just make the port the server connects to on the switch a routed port and assign the IP directly to the port although for end devices this is not seen very often primarily because very few people use /30s for end devices.
Either would work but 2) will only if there is a single server per subnet.
If you wanted security between servers you would need to use acls to restrict the traffic. If you need more security than acls then you probably shoudn't be using a L3 switch.
As for routing to and from this subnet, it's not possible to say without knowing more of your topology ie. how does traffic get routed to the 3750 ? Your 3750 would need to know how to route to remote subnets and your other devices would need to know how to route to the /24 subnet being used on the 3750.
Note that although using /30s on the 3750 does waste addresses for any other device that needs to route to the 3750 you can simply use the /24 route because the actual subnet mask in use only becomes relevant on the 3750 if you see what i mean.
If have misunderstood what you are trying to do please explain further.
Jon
