Slow download on docker build - 1.12.0-rc3-beta18 (build 9996)

Expected behavior

Container creation
This image takes like less than 10 minutes to build, now takes by an hour and never ends.

Actual behavior

Packages really slow download, temporal container still run but never complete the task,

Information

269F8ACE-C09C-4FB4-856C-8208C92B0020

Even I download the ubuntu package from host and take like 2 minutes but on container I wait like 45 before I stopped. Tried again on host an again 2 minutes.

i get in the container using docker exec -ti container-name bash and tried to download the package manually inside the container but nothing to, to slow.

269F8ACE-C09C-4FB4-856C-8208C92B0020

I stopped docker and the build was completed as normal.