Comment 23 for bug 1409661

Roman, you gave a link to cpython function address_string.
Was same function used in prior releases? Do you have idea, why this issue appears only in 6.0?

Also, I think both root causes should be fixed:
1) Reverse dns lookups used.
 2) Wrong /etc/dnsmasq.conf on fuel master, that tries to forward requests to public dns server (it is similiar thing as in https://bugs.launchpad.net/fuel/+bug/1393605)