Please use a dumper module to display the content of your hashes rather than try to print them, not only will it help tell if a value is actually defined or the empty string, it will also make it much easier for us to try and reproduce your defect.

And if you're going to use the same deep-level element several times in a row, please use a temp variable for readability: my $ioRef = $moduleRef->{modRef}{$moduleName}{ioRef}; With that you'll be able to call keys %$ioref; and $ioref->{$net}. It also helps make sure you are actually always accessing the same thing.

Also, your output doesn't match your code. Your code prints "$net is part of hash " but your output has "is hash part of hash", so either you are not giving us the output you got from that code, or you are working with the wrong file.