We use a lot of IPs. Over 14,000 currently, with more and more every day.
Fortunately, there are a lot out there (over 4 billion, even before IPv6), so we really aren’t in any great danger of running out.
Except we are!
You see, even though there theoretically are 4 billion IP addresses, it isn’t just a big pool of digits for any web host to dive in and scoop up whatever they want, whenever they want, however they want, whomever they want.
Instead, you have to apply to your Regional Internet Registry when you want more, in a process somewhat similar to that of registering domain names. However, because IPs are in relatively short supply (only 4 billion, as opposed to the almost one GOOGOL possible .com domain names) you can’t just buy as many you want! You actually have to apply and prove that you’re deserving of more IPs.
That’s a good thing though… the Internet would be in big trouble if say Microsoft decded to buy up all the remaining IPs in the world! IPs aren’t nearly as expensive as domains (you can get a “/14” (262,144 IPs) for $18,000/year .. just 7 cents each!)… so in theory, Microsoft could buy ALL existing IPs for about $250M/year. For a $40B company, I think that might be worth it to basically OWN THE INTERNET!
To I guess prevent this from happening, and to keep people from being careless and wasteful with such a limited resource, ARIN will only let you get more IPs if you’ve already used 80% of the ones they’ve assigned to you. To prove it, you have to send them a report of the IPs in your last allocation and how they’re being used, which they even then check!
That seems fine and dandy, except for just one problem. The threshold isn’t 80% of your total IPs, it’s just 80% of the last allocation you received.
Which is why we’re in trouble!
We’re well over 80% utilization for ALL our IPs, and because of the exponential nature of our growth, and the sometimes slow process of getting more IPs from ARIN, we feel now is the time to get more IPs so we don’t run out (which would be… very bad).
The last time we applied for some IPs, we asked for a “/19” (8192 IPs), but they only gave us a “/20” (4096). This means that they won’t approve our application for more IPs until we have only 819 left. Which therefore means, we really can’t get more IPs until we’re 95% full… cutting it a little close, ですね?!
And, 819 IPs may sound like plenty, but really it’s not, because for ease of administration we allocate chunks of our own IPs among our various services. So there are chunks of IPs that are reserved for web servers, chunks reserved for https and anonymous ftp, chunks reserved for mail servers, chunks reserved for database servers, and so on and so on.. and if ANY of these chunks run out we start to have problems and have to allocate them another chunk (which is generally 256 or 128 IPs all at once).
What to do?
Well, there’s only one thing to do, which is pretty silly, and is what we’ve done.
We’ve used a lot of our newest allocation of IPs on things that already had IPs assigned from our original allocations! We then freed up the old IPs and are going to keep available a huge chunk of emergency IPs from that. We’ll only use those IPs if we ever run out of IPs in our newest allocation before ARIN assigns us some more.
By moving IPs from our original allocations to our most recent one, we were just able to get our usage up to 80.1%! So we’ve submitted our application, which will hopefully go through with plenty of time before we have to start delving back into our old IP space. We’ll probably be fine.
It’s just annoying to have to do such a meaningless re-ordering of our network, just because ARIN goes by 80% utilization of your last allocation, instead of your entire allocation.
C’mon ARIN, change dat!