John Lim, CTO TekTegrity

By John Lim, CTO

The Internet has a protocol for packaging information and transmission of said information, and that Internet Protocol (IP) requires addressing. When you go to,, or, all of those names resolve to one or many IP addresses on the backend and gets your applications to pull data from those servers. All of these providers has unique public IPs that only belongs to them.

So how many IP addresses are available? For this conversation, we will stick to IPv4 addressing and not delve into IPv6 (Another whole ball of wax). There are roughly Four Billion available IPv4 public addresses available. That’s a lot, but how many connected devices do we have in the world? In 2016 IHS Market estimates that there are roughly 8.5 Billion devices and that list keeps growing exponentially. Anyone hear about IoT (Internet of Things)? So if EVERYTHING gets an IP address how does this all work? We do NOT have enough unique addressed to go around!?!

To help with the exhaustion of IPv4 addresses, way back in the day super smart people started using Network Address Translations(NATs) and Routers to create a private IP subnets (range of private IP address) to bridge into public IP subnets (unique public IP addresses). When these smart people started chatting with other smart people, they decided that this is a great idea and that a standard should come out of this. So in 1996, the IETF put out RFC 1918 to help standardize the use of IP address for private use. There are three blocks of IP addresses reserved for Local Area Network (LAN) use. We have (~16 million addresses), (~one million addresses), and (~65 thousand addresses).

As most of you have noticed, at home, most of your Wifi/Routers will have all of this programmed in when you connect it to your Internet Service Provider and your devices will auto-magically have an IP address behind your router of something like or something very similar and then you can start binge-watching Netflix. Standardization!

This is great and all but why do I care? For home, I would not care one bit. For your business, this is where your IT Provider will start caring. So many times I have seen businesses setup with a non-private IP address subnet or are placed into a subnets. Everything is working, why should I care? I am so happy that everything is working, but for your IT Provider, I’m sure it drives them crazy at times. There are hidden or potential problems that will eventually creep up.

If you have a non-private IP address subnet for your LAN, this basically means your Router will NEVER be able to route you to whatever is hosted on the internet that actually is registered to that IP address subnet that you are using privately. So say for some reason, your private IP address subnet is NOT using a standardized IP address subnet and is using –, then SOMETIMES you will not be able to go to Yes, I said sometimes and not all the time because has multiple IP addresses (REDUNDANCY!).

Scenario number two. Let’s say your office is on a standardized private IP address subnet of That’s great! You can get anywhere. Now you are at home and your home private IP address subnet is also Great again! You can get anywhere. Now you need to do some work from home and your IT Provider for your office set you up with a Virtual Private Network connection to your office so you can pull files remotely and work on them. Nothing is working, I’m not working! Well, basically your subnets conflict. Too many times I have seen businesses setup with IP addresses on subnets that are typical setups for consumers and consumer products. This should be avoided.

All of this stuff is boring. Yes, it’s super boring but your IT Provider lives for this stuff and freaks out about it at times. Regular people should not even care, but IT people do and should. I promise next month’s article will be even more boring, Domain Name Services!!!

//John, CTO directs our team of technicians in support cases, new project planning, and research and development. John came to TekTegrity after spending ten years as a leader in Cuesta College’s Information Technology Department where he helped make possible Cuesta’s High Tech building, myCuesta portal, and Gmail integration. If you come by the office and there are dozens of donuts, bagels or fresh egg rolls (from San José) in the break room, John is most likely the food fairy who left them. And if he’s not feeding or directing the tech team you might find John having lunch at the Elks Lodge or spot him cruising the coast with his motorcycle gang.