Another thing to try (google first) is to blacklist the ipv6 module. This is what I normally do for my other linux systems. Before somebody says "you shouldn't disable IPV6", there are definitely some network setups in which IPV6 doesn't play nicely. Some legacy servers/devices won't play well, and if IPV6 gets the first byte (couldn't resist) of the cherry, it will fail, and timeout eventually. To save this delay, you could fix the legacy device, or just disable IPV6. Time is money, so everyone here disabled IPV6
Going through the sys system is another way - and works just as well. The only difference is that blacklisting stops IPV6 from even starting. You can check which interfaces IPV6 is running on with:
cat /proc/net/if_inet6
Sorry, didn't see this thread on the weekend, I was away.