Using urllib2.urlopen i get different errors from local vs AWS EB

I have this snippet in a python 2.7.6 app:

try:
    response = urllib2.urlopen(req, timeout=20)
except:
    warning(sys.exc_info())

When I run it locally on my machine i get the error:

(<class 'urllib2.URLError'>, URLError(gaierror(8, 'nodename nor servname provided, or not known'),), <traceback object at 0x10ca40b00>)

When I run it on AWS EB I get

(<class 'urllib2.URLError'>, URLError(gaierror(-5, 'No address associated with hostname'),), <traceback object at 0x7f59958a1050>)

Why do I get different error messages? I believe I running the same versions of everything in both environments.