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NAT loopback

(also hairpin NAT)

NAT loopback definition

NAT loopback, also known as hairpin NAT, is the feature where a router can route a network request from a device back within the same network rather than directing it to the internet. This capability becomes indispensable when a device on the network endeavors to connect with another device on the same network via the external (public) IP address or a domain name associated with that IP address.

See also: NAT traversal, static IP, dynamic IP

NAT loopback examples

  • Home security: If a home security system is configured to be accessible over the internet and an individual within the same home network tries to access it using the external IP address, NAT loopback allows this to happen smoothly.
  • Remote desktop: Users trying to connect to their desktop machine from a laptop within the same network via the external IP address or domain name would need NAT loopback for a successful connection.

Advantages and disadvantages of NAT loopback


  • Convenience: Enables devices in the same local network to communicate using their public IP addresses or domain names, which can simplify network management and use.
  • Consistency: NAT loopback allows the same URL or IP address to be used for a service, whether accessing it from the local network or the internet.


  • Security concerns: If not configured correctly, NAT loopback may open up more of the network to potential intrusion.
  • Router support: Not all routers support NAT loopback.

Using NAT loopback

  • Ensure the router supports NAT loopback, or consider a router upgrade if this feature is essential for network activities.
  • Exercise due caution and apply necessary security measures when enabling NAT loopback.