Lightning Network: is it possible to run an LN node behind NAT?
Anyone can freely set up their own LN node and connect it to the decentralized Lightning Network. However, the connection to the Internet often passes behind NAT, i.e. Network Address Translation, which “translates” public network addresses into internal IPs of the local network.
How to run an Lightning Network node behind NAT?
There are many home connections in the US that are using NAT, so it may be a problem to install an LN node using one of these connections to connect it to the network.
According to the Coinmonks guide, LND has a special ‘nat’ function that allows the node to be made public to the entire network even if it is using a single NAT. The function automatically handles changing the public IP address, so that fewer scripting tricks are needed on the node.
The alternative would be to manually use scripts on the node itself.
Lightning Network Daemon
LND is the Lightning Network Daemon, which is a complete implementation of a Lightning Network node in which the developers have paid a lot of attention to the issue of security and privacy.
LND enables full management of all channel states, including exceptional ones, and is fully compliant with the Lightning Network BOLT specification, i.e. Basis of Lightning Technology.
LND has also been designed to be as developer-friendly as possible to facilitate application development.
In addition to the NAT function, it is a lightweight client that reduces disk space requirements, and also offers automatic channel management (autopilot).
This function requires adequate hardware support, and is only compatible with devices with single NAT, not multiple NAT.
To detect hardware support, the gateway address of the router is retrieved, so that it can automatically retrieve the external IP address, even if it changes over time in the case of dynamic IPs, and broadcast it on the network using the ports on which the daemon is listening.
A similar procedure can also be used to install a Bitcoin full-node, because if the machine on which it is installed is behind NAT, there is a risk that it will be able to send data, but not receive it.