I have started to work in a multinational company which has a global network spanning across 4 continents (20 0000+ network devices).
I noticed that a lot of end user devices (PCs, laptops) have IP addresses like 22.17.218.151, 124.0.42.16, 35.16.42.11, etc., i.e. public IP addresses. And absolute majority of those devices have the connection to the Internet.
I suppose network designers consciously chose to use public IPs inside private networks? But there must be some justification in doing so? In which cases is it beneficial to have public IP addresses within private networks?
And what are the downsides/pitfalls of this scheme? What if a company's PC with "local" IP 22.17.218.151 tries to access some 3rd party resource on external network which public IP is incidentally 22.17.218.151 ?
Public IP Addresses in Private Networks – Why Use
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Best Answer
The first thing you need to figure out is whether the public addresses in your network are in fact assigned to your company.
If the answer is Yes, it's likely because those addresses were available to use and address space wasn't an issue at the time. There is no problem in using public addresses, and it has one advantage of making troubleshooting easier.
If the answer is No, then you have a problem. As you point out, if you use someone else's addresses inside your network, you will not be able to reach those addresses on the Internet.