lbry.com/content/faq/how-to-change-port.md

title	category
How to change default daemon peer port?	setup

If you see the error message couldn't bind to port 3333, it is likely that another process is already bound to that port. You will need to change the port before starting the daemon.

To change the port once during runtime, set the LBRY_PEER_PORT env variable. Here's one way to do this:

LBRY_PEER_PORT=3334 ./lbrynet-daemon

Once the daemon is running, you can change the port permanently by using the following api call

curl 'http://localhost:5279/lbryapi' --data '{"method":"settings_set", "params":{"peer_port":<port-num>}}'

or via cli command

lbrynet-cli settings_set --peer_port 3333