def scan(addr):
    try:
        global Host_name
        f = gevent.socket.gethostbyaddr(addr)
        Host_name = f[0]
        print(Host_name, ' - ', addr)
    except:
        pass
def scanfornames():
    x = input('Input first 3 octets of the network:(X.X.X.):')
    addrs = [x + str(i) for i in range(255)]
    jobs = [gevent.spawn(scan, addr)for addr in addrs ]
    gevent.joinall(jobs, timeout=5)
    #jobresults = [job.value for job in jobs]
    end = input('Restart scan? y / n     ')
    if end == 'y': scanfornames()
scanfornames()

 import gevent
from gevent import socket
import time
def scan(addr):
    try:
        global Host_name
        f = gevent.socket.gethostbyaddr(addr)
        Host_name = f[0]
        print(Host_name, ' - ', addr)
    except:
        pass
addrs = ['192.168.198.1','192.168.198.130', '192.168.198.129', '192.168.198.131']
def scanfornames():
    jobs = [gevent.spawn(scan, addr)for addr in addrs ]
    gevent.joinall(jobs, timeout=2)
for i in range(20):
    scanfornames()
    time.sleep(0.02)
    print('----------------------greenlet done------------------------')

 #!/usr/bin/env python
import sys
import gevent
#from gevent import socket
import socket
addrs = ['192.168.198.1','192.168.198.130', '192.168.198.129', '192.168.198.131']
def job(addr):
    try:
        url = socket.gethostbyaddr(addr)
        print addr,':',url
    except Exception as e:
        print addr,str(e)
        
for addr in addrs:
    jobs = [gevent.spawn(job,addr)]
    gevent.joinall(jobs,timeout=1)
    
sys.exit()

 #!/usr/bin/env python
import sys
import gevent
from gevent import socket
addrs = []
urls = ['www.google.ru',
        'www.yandex.ru',
        'www.python.su',
        'www.ya.ru',
        'www.youtube.com'
        ]
def job(url):
    try:
        ip = socket.gethostbyname(url)
        print url,ip
        addrs.append(ip)
    except Exception as e:
        print url ,e
def job2(ip):
    try:
        url = socket.gethostbyaddr(ip)
        print ip,url[0]
    except Exception as e:
        print ip ,e
    
        
for url in urls:
    gevent.spawn(job,url).join(timeout=1)
    
for addr in addrs:
    gevent.spawn(job2,addr).join(timeout=1)
sys.exit()