FTP proxy based on AbstractFtpProxy, enabling read-only access to any user. Commands and return codes are strictly checked, unknown commands and responses are rejected. Every feature is accepted.

The ABOR; ACCT; AUTH; CDUP; CWD; EPRT; EPSV; FEAT; LIST; MODE; MDTM; NLST; NOOP; OPTS; PASV; PASS; PORT; PWD; QUIT; REST; RETR; SIZE; STAT; STRU; SYST; TYPE; and USER commands are permitted, the CLNT; XPWD; MACB commands are rejected.