CPAN modules for getting module dependency information is worth taking the time to read, note that some options covered here won't meet your needs as they require internet access. I'm in a similar situation for a client. No internet access from servers. I use minicpan to create version of cpan, which is then transferred to a suitable area of the clients network. Then I configure cpanm/cpan to point to the cpan mirror on the client network and use these tools as normal.