Similar issue: https://bugzilla.redhat.com/show_bug.cgi?id=737230
but as noted earlier here: cups-1.5.3-2.4.1.x86_64
That bug report also asked for a few things, but this is now just shooting in the dark:
$ python -c 'import socket;print socket.getaddrinfo("localhost", 631)'
(10, 1, 6, '', ('::1', 631, 0, 0)), (10, 2, 17, '', ('::1', 631, 0, 0)), (10, 3, 0, '', ('::1', 631, 0, 0)), (2, 1, 6, '', ('127.0.0.1', 631)), (2, 2, 17, '', ('127.0.0.1', 631)), (2, 3, 0, '', ('127.0.0.1', 631))]
$ ip addr show dev lo
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 brd 127.255.255.255 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
$ egrep -v $'^ ]*(#|$)' /etc/hosts
127.0.0.1 localhost
192.168.10.9 goflex
192.168.1.254 modem
192.168.10.1 router
::1 localhost ipv6-localhost ipv6-loopback
fe00::0 ipv6-localnet
ff00::0 ipv6-mcastprefix
ff02::1 ipv6-allnodes
ff02::2 ipv6-allrouters
ff02::3 ipv6-allhosts