ftp problem

Hi ALL
I have searched for this answer buy couldnt find it so hence asking desperately for your help

I am on a network and FTP seems to work fine when on the network. But when i try and use from outside the network, from home. To test it i use IE, and from outside it wont even bring up the login box.

Any one help and explain how i can resolve this? is it a firewall issue?

Your help will be greatly appreciated people

Thanks