use std::io::{Result, Error, ErrorKind};
use std::net::TcpListener;

fn main() -> Result<()> {

    let listener = (60000u16 .. u16::max_value())
        .find_map( |port| {
            TcpListener::bind(("0.0.0.0", port)).ok()
        })
        .ok_or(Error::new(ErrorKind::Other, "no port found"))?;

    println!("port: {}", listener.local_addr()?.port());

    Ok(())
}