How do you make it so that a user can't go up any higher in the file tree than his home directory using FTP (note: i'm using vsftpd)?
the easiest and prolly safest way is to chroot local users on ftp accesses.
There is a switch it vsftpd.conf iirc
Yep, just set chroot_local_user=YES in vsftpd.conf.
OK, that worked. I have another question: If I attempt to connect to my FTP using the local network address while inside my network I can connect no problem. However, when I try to connect using my external IP or my dynamic DNS address, I get the following message:
425 Security: Bad IP connecting.
What can I do to fix this problem?
Quick googling revealed, that you should set pasv_promiscuous=YES in order to make it work. It seems that your data connection originates from the other IP than your control connection. I don't know what's the reason for it, you could research it some more :-) Maybe you should try disabling pasv connection, if active works for you. I'm far from being an expert in that field :-)