Let's assume we are talking about IPv4 and not IPv6. You can either do one of the following

 

1. Place static ARP entries on your switches/routers; Cisco IOS style would look like this,

 

arp 10.10.10.10 00ac.a3f3.09ab area 

 

Keep in mind there are other ways, it all depends on your platform;

 

2. You could also subnet your IPv4 allocation, i.e. split it into several subnets. Allocate one every VPS customer. They won't be able to grab and use IPs outside of their allocation, but you will be wasting your IP space on the extra gateway, loopback, etc. Another question that arises is what if customer today has close to 30, but tomorrow require more IPs (like /29 or /28), you'd have to re-design your existing subnet or/and migrate them. This is important and needs your active consideration.

 

3. Also, it depends on what virtualization platform you utilize, e.g. VMware, XenServer and so on and so forth.

 

4. You must state in your AUP & Agreements that Clients shall use only that IPs that are assigned to them and must not use any IP addresses outside of their assigned range. You could write some scripts to monitor IP usage on your virtual platform, router or switch, and report back, so you can take corrective action.

 

Another Option

 

 

If you start a business selling VPS containers, then you sure will use one of the mainstream admin panels to create and administer those containers 'Tab F' just mentioned SolusVM above (which has its problems with backups, that they promised us to solve since YEARS now, but haven't). Anyway, whatever panel you choose, and you should get one, if these VPScontainers are not just for your own use, then this question becomes invalid.