Ok, first thing is that we get test cases straight so that we are talking apples to apples! I tested with this site:
ftp://ftp.perl.org/pub/CPAN/authors/01mailrc.txt.gz

You should even be able to cut'n-paste that exact thing into your web browser and get a response.

When you change the test URL case to ftp.cpan.ddns.develooper.com that can change things. When I saw this, I thought hey, there is an extra "o" in developer, but no, this a valid URL! And this URL works in FireFox and I even tested with IE.

update: I see that you have tested this. well this is a firewall / proxy deal.