root@support:/home/ftp# ls -ld .
drwxr-xr-x 3 root root 4096 Jun 22 00:00 .
root@support:/home/ftp# ls -ld pub
drwxr-xr-x 3 root root 4096 Jun 21 23:59 pub
root@support:/home/ftp# ls -ld pub/upload
drwxr-xr-x 2 ftp ftp 4096 Jun 22 00:06 pub/upload
root@support:/home/ftp#

root@support:/home/ftp# grep -v '#' /etc/vsftpd.conf
listen=YES
anonymous_enable=YES
write_enable=YES
anon_upload_enable=YES
dirmessage_enable=YES
xferlog_enable=YES
anon_root=/home/ftp/pub/
connect_from_port_20=YES
chown_uploads=YES
chown_username=ftp
nopriv_user=ftp
secure_chroot_dir=/var/run/vsftpd
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key

root@support:/home/ftp/pub/upload# ls -l
total 0
-rw------- 1 ftp nogroup 0 Jun 22 00:06 build.out

$ ftp 173.203.89.78
Connected to 173.203.89.78.
220 (vsFTPd 2.0.6)
User (173.203.89.78:(none)): ftp
331 Please specify the password.
Password:
230 Login successful.
ftp> put build.out
200 PORT command successful. Consider using PASV.
553 Could not create file.
ftp> cd upload
250 Directory successfully changed.
ftp> put build.out
200 PORT command successful. Consider using PASV.
150 Ok to send data.