Virtual host ftp provides anonymous ftp access for different domains on a single server. Each virtual host is linked to one directory on the server.
The FTP protocol does not carry enough information to support
virtual hosting. This means you need one IP per virtual host
(IP aliases) on the server. The wuftpd server does a reverse lookup
on the target IP and finds the proper virtual host to serve.
This means you need either proper DNS settings or a properly
filled /etc/hosts file.