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What is the difference between a Public and a Private fixed IP address?

Posted on 03-02-2016 , by: Anvil Mobile , in , 0 Comments

After reading this blog, you will understand what a Public and a Private fixed IP address are and how they differ. Anvil Mobile have consulted many companies, from SMEs to large corporations, on the type of fixed IP address they need.

What is an IP address?

An IP address is a unique set of numbers, connected by full stops, that identifies each device using the Internet Protocol to communicate over a network.

Public IP address

A public IP address can be accessed from anywhere in the world where you have an internet connection using any device with a browser. This means that you can use a PC, tablet or smartphone to connect to an Anvil SIM and forward that internet connection to any device connected to the 3G/4G router.

With a public IP address, multiple people can access the device or service from multiple locations although only one user can connect at a time. Public IPs are simple to implement and use, however, they are more vulnerable and, therefore, users have to be vigilant in protecting the device or service. Most 3G/4G routers have settings and integrated firewalls specifically for this purpose.

Private IP address

Private IP addresses cannot be seen via the internet as they are in effect an internal network/closed group. Only people with access to that internal network can reach the private IP address and consequently a VPN is needed between the core network and the customer’s network.

While more secure, as the private IP addresses are invisible to the general public, the set-up is more complex as it requires some design, resources and costs. To gain access from multiple customer locations requires secure access into the VPN either through a direct connection or some form of VPN client which would normally be Windows PC based.

In practice, private IP address ranges tend to be used where there is a sufficient quantity of SIMs and devices to justify the time and set-up costs. For a single SIM connection, this would be an expensive option whereas for several hundred SIMs it becomes a highly secure and viable option.

Which one is for you?

Fixed Public IP addresses on 3G/4G data SIMs are suitable for companies and organisations that benefit from being able to remotely manage systems where there is either no fixed line available or fixed lines would be prohibitively expensive. For instance, providing remote management and control of renewable energy systems in rural areas or connecting to a remote CCTV security camera. If this suits your business needs then it is important to remember to configure the 3G/4G router with the appropriate security settings.

Private IP addresses are for businesses that are ordering a large number of SIMs where security and control are paramount. In this case, an industry example would be providing 3G/4G back-up across a network of retail stores so that even if the DSL broadband line fails, the stores stay open and business continues as normal.


For more information, get in touch with Anvil Mobile today. Call 01799 218033 or email [email protected]