scan.py

import asyncio

@asyncio.coroutine
def scan_remote(host, port, timeout=1):
    try:
        connection = asyncio.open_connection(host, port)
        yield from asyncio.wait_for(connection, timeout)
    except (OSError, asyncio.TimeoutError):
        pass
    else:
        print("Connected to {}:{}".format(host, port))

@asyncio.coroutine
def scan_hosts(hosts, port):
    # Scan a given port against a list of hosts
    yield from asyncio.gather(
        *[scan_remote(host, port) for host in hosts])

@asyncio.coroutine
def scan_ports(host, ports=range(1, 1024)):
    # Scan all the ports of a given host
    yield from asyncio.gather(
        *[scan_remote(host, port) for port in ports])


# Example: scan for port 22s in 192.168.0.X

hosts = map('192.168.0.{}'.format, range(256))
asyncio.get_event_loop.run_until_complete(scan_hosts(hosts, 22))