Jun-ichiro itojun Hagino <itojun@itojun.org>:

Now first check if IPv6 is supported, then use PF_UNSPEC. If not, use PF_INET.
It'll solve both the "slow name lookup" problem on IPv4 and still work fine on
IPv6 hosts.

Bug report #530204 has more details:
http://sourceforge.net/tracker/?func=detail&atid=100976&aid=530204&group_id=976