Invalid LAN Subnet

Why public IP Addresses can not be used for local networks?  

All IPv4 IP addresses can be divided into two major groups:  public IP Addresses that are used in the Internet, and private IP addresses that are used in the local network (LAN). 

If your local network is using public IP addresses space, and the Public IP address is in conflict with some external website, you may not be able to access the site, because the request will be routed to your local network instead of the Internet. 

What is a private network? 

• Range from 10.0.0.0 to 10.255.255.255 — a 10.0.0.0 network with a 255.0.0.0 or an /8 (8-bit) mask
• Range from 172.16.0.0 to 172.31.255.255 — a 172.16.0.0 network with a 255.240.0.0 (or a 12-bit) mask
• A 192.168.0.0 to 192.168.255.255 range, which is a 192.168.0.0 network masked by 255.255.0.0 or /16

For more details, see https://en.wikipedia.org/wiki/Private_network

How to change my LAN subnet?

Here are some examples of how this is configured on popular routers. If your router is not on this list, please refer to your router's manual. 

• Netgear

  Official Guide: https://kb.netgear.com/000060898/How-do-I-change-the-LAN-IP-address-settings-for-a-LAN-subnet-on-my-BR500-router
  
  

• Ubiquiti

  1) Login to your Ubiquiti router.
  2) Navigate to Settings -> Networks -> LAN
  3) Change the IP Address field.
  4) Save and confirm.

• Asus

  Official Guide: https://www.asus.com/support/FAQ/1011245/
  
  

• Linksys

  Official Guide: https://www.linksys.com/us/support-article?articleNum=142466