Need a little bit help with Linux on seedbox

Hi all,
I'm going to share seedbox with my friend. My seedbox has 160GB HDD, has 2 IPs, and the Linux distro is Debian, what I'm going to ask is :
1. after adduser user_name, does it need also to set up the group for that user so my friend can also use the rTorrent installed on behalf of root ?
2. how do I set the new user home folder quota, so it's limited to 80GB only ?
3. is there any other settings need to be done so my friend with the new user name could log into the seedbox using the other IP ?
4. usually I use SFTP to make the transfer, but my friend wants to use FTP, I checked, seems like no FTP server installed, could anyone provide me with a short tutorial about installing ProFTPd into Debian, also how to make the account could log into ProFTPd ?


thanks a lot

1. I don't think so
2. I don't know how to do this, but I think the setquota command might work. Besides, is it really necessary?
3. Does your server responds to the 2nd ip? If not, you gotta add the 2nd ip as another interface (most likely eth0:0). I'm not sure how to do this off the top of my head with debian. Most likely, you'd have to add another interface in /etc/network/, and use commands like ifconfig, ifup, ifdown, etc. To force the 2nd user to use the other IP, you'd have to add an entry to iptables. Or there's a setting in utorrent to do this, but I don't know if there's one for rtorrent.
4. I personally use vsftpd, I think it's simpler to setup than proftpd. To let local users login, you just have to change that setting somewhere in vsftpd.conf. Simple guide here: http://www.debianhelp.co.uk/vsftpd.htm

1. No, you do not need the group, its optitional. And what do you mean by installed on behalf of root? If you installed it via apt he should be able to use it. Do not run any torrent client as root.
3. I dont think it matters which ip he uses to login to your box. The only ip that matters is the ip his torrent client uses and you should be able to set that in the config.
4. If its somehow possible, dont use ftp. Its all plaintext (so its really insecure, everyone between him and your server could sniff your password). There are many good Sftp/fish clients for every platform, use them, for example winscp (windows) or cyberduck (osx).