Traceback (most recent call last):
File "./se3.py", line 16, in <module>
dr=webdriver.Firefox(firefox_binary=binary,executable_path=driver_path)
File "/opt/python36/lib/python3.6/site-packages/selenium/webdriver/firefox/webdriver.py", line 154, in __init__
keep_alive=True)
File "/opt/python36/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 151, in __init__
self.start_session(desired_capabilities, browser_profile)
File "/opt/python36/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 240, in start_session
response = self.execute(Command.NEW_SESSION, parameters)
File "/opt/python36/lib/python3.6/site-packages/selenium/webdriver/remote/webdriver.py", line 308, in execute
self.error_handler.check_response(response)
File "/opt/python36/lib/python3.6/site-packages/selenium/webdriver/remote/errorhandler.py", line 194, in check_response
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: failed to lookup address information: Name does not resolve

一開始以為是geckodriver的問題，於是在不同的geckodriver換來換去，firefox也試過不同的版本，然而並沒有解決。百度了一下也沒有相關的問題。

最後還是看錯誤信息，failed to lookup address information: Name does not resolve，

啟動geckodriver的時候1508740937900 geckodriver INFO Listening on 127.0.0.1:4444

想到會不會是/etc/hosts的問題，於是在/etc/hosts上添加

127.0.0.1 localhost

問題解決。

selenium 3.6.0 geckodriver的一次坑