Offline Ports Tree

[Ihor Antonov]

Hi,

I am trying to figure out if I can have a fully offline, self-sufficient
ports tree.

Just the ports tree itself contains instructions how to build things
and how to fetch the sources. Is there an automated way download all the
source tarballs (and clone all git/svn repos) that ports refer to? 
The goal is to be able to build ports in an offline environment.

Thanks.