if (rc == 550) {

        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,

                     "proxy: FTP: RETR failed, trying LIST instead");

        /* Directory Listings should always be fetched in ASCII mode */

        dirlisting = 1;

        ftp_set_TYPE('A', r, origin, bb, NULL);

        rc = proxy_ftp_command(apr_pstrcat(p, "CWD ",

                               ftp_escape_globbingchars(p, path), CRLF, NULL),

                               r, origin, bb, &ftpmessage);

        /* possible results: 250, 421, 500, 501, 502, 530, 550 */

        /* 250 Requested file action okay, completed. */

        /* 421 Service not available, closing control connection. */

        /* 500 Syntax error, command unrecognized. */

        /* 501 Syntax error in parameters or arguments. */

        /* 502 Command not implemented. */

        /* 530 Not logged in. */

        /* 550 Requested action not taken. */

        if (rc == -1 || rc == 421) {

            return ap_proxyerror(r, HTTP_BAD_GATEWAY,

                                 "Error reading from remote server");

        }

        if (rc == 550) {

            return ap_proxyerror(r, HTTP_NOT_FOUND, ftpmessage);

        }

        if (rc != 250) {

            return ap_proxyerror(r, HTTP_BAD_GATEWAY, ftpmessage);

        }

        /* Update current directory after CWD */

        cwd = ftp_get_PWD(r, origin, bb);

        if (cwd != NULL) {

            apr_table_set(r->notes, "Directory-PWD", cwd);

        }

        /* See above for the "LIST" vs. "LIST -lag" discussion. */

        rc = proxy_ftp_command((cwd == NULL || strchr(cwd, '/') != NULL)

                               ? "LIST -lag" CRLF : "LIST" CRLF,

                               r, origin, bb, &ftpmessage);

        /* rc is an intermediate response for the LIST command (125 transfer starting, 150 opening data connection) */

        if (rc == -1 || rc == 421)

            return ap_proxyerror(r, HTTP_BAD_GATEWAY,

                                 "Error reading from remote server");

    }