yeah I agree filezilla server works and is very easy to configure and run.
But to be honest I would not open just plain ftp to the public internet. Ftps -- and you can run into some pain with ftp data and control channels, depending if your using passive or active. And when using ftps there is implicit and explicit. When you run ftps and the control channel is encrypted many routers have issues with the ftp helper and can not see the data port so you need to open them via port forwards, etc.
I would suggest you use sftp which is just 1 port and secure default is 22 (ssh port) and much easier to use with nat. Or look into something that provides you web access to your files. Dropbox for example - you can keep copy of files in the cloud. And can access via web interface if need be.
Or setup VPN or ssh tunnel into your network to do you ftp over.
FTP while still viable protocol is very dated and problematic to setup when your normally behind 2 nats, your location and the location your ftping too, etc.
There are much easier ways to skin the cat these days -- how many files are we talking space wise?
@Jub -- he asked for servers not clients.
BTW - http://www.freesshd.com/
is windows sftp
server. There are few others but having a hard time remembering names of them.. You could run one in cygwin if need be. But any linux distro has ssh/sftp
out of the box and is very easy to run via a vm and then just mount your window shares if need be, etc. Like I said many ways to skin the cat.
Best option to getting to your network remotely is vpn hands down, openvpn is free, etc.