Hi there! I'm also a linux beginner and have come around with vsftpd.
I have set things up before and its working fine.

Just when I have to access the ftp, i got this error:
500 OOPS: vsftpd: cannot locate user specified in 'ftp_username':ftp

When I copied the codes to be added on /etc/shadow and on /etc/passwd, it did make it connected after saving them and restarting the vsftpd under root user.

I was just wondering , that have any thing i have done previously in my linux box, that removed those codes that are inplace before? Because actually it did run for sometime until before some changes i made with my linux box, installed vmware and tested its capability and some other chages too.
Is it true that due to changes i made, that removed those codes in the /etc/shadow and /etc/passwd? Why is it?