How do I find out if my ISP has put me behind a NAT. Will Dynamic DNS work with my ISP? (2024)

When setting up a VPN on my office LAN, I first need to setup a way to access my local network over the internet.

There are 2 ways to do this

1. Buy static IP address (Paid)
2. Configure Dynamic DNS (Almost free)

But, in order for the option 2 to work, the office router should have a direct public IP address.In another words, the ISP (Internet Service Provider) should not put the router inside a NAT. Which basically means that if the router is behind another network device, it will not have a direct public IP address.

In US for example, 98% home users will have public IP assigned to the router.However, in India, most probably, the ISP will but the router behind a NAT.

Hence, the question: How do I find out if my ISP has put me behind a NAT. Will Dynamic DNS work with my ISP?

• 1

  Note that NAT does not necessarilly mean this won't work. the question is whether the NAT method in use has one public IP per internal customer, and whether they give you control of the NAT at your router (which is common with north American ISPs). Some kinds of NAT like Carrier-Grade NAT will make this almost impossible, but other types will allow you to do what you need to. Also note that DynDNS does two things for you, it lets your router update your public IP as it changes, and gives you a domain name to run your services on. your router does need to support DDNS updates though.

  –Frank Thomas

  Mar 2, 2021 at 0:23

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