The /etc/ftpconversions file contains instructions that permit you to compress files on demand before the transfer.
    
      Edit the ftpconversions file, vi /etc/ftpconversions and add in this file the following lines:
      
        :.Z:  :  :/bin/compress -d -c %s:T_REG|T_ASCII:O_UNCOMPRESS:UNCOMPRESS
        :   : :.Z:/bin/compress -c %s:T_REG:O_COMPRESS:COMPRESS
        :.gz: :  :/bin/gzip -cd %s:T_REG|T_ASCII:O_UNCOMPRESS:GUNZIP
        :   : :.gz:/bin/gzip -9 -c %s:T_REG:O_COMPRESS:GZIP
        :   : :.tar:/bin/tar -c -f - %s:T_REG|T_DIR:O_TAR:TAR
        :   : :.tar.Z:/bin/tar -c -Z -f - %s:T_REG|T_DIR:O_COMPRESS|O_TAR:TAR+COMPRESS
        :   : :.tar.gz:/bin/tar -c -z -f - %s:T_REG|T_DIR:O_COMPRESS|O_TAR:TAR+GZIP
        :   : :.crc:/bin/cksum %s:T_REG::CKSUM
        :   : :.md5:/bin/md5sum %s:T_REG::MD5SUM
      
        Now, change its default permissions to be 600:
        
          [root@deep ] /# chmod 600 /etc/ftpconversions
        
        Configure your /etc/pam.d/ftp file to use pam authentication by creating  the /etc/pam.d/ftp file and add the following lines:
        
          #%PAM-1.0
          auth       required     /lib/security/pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed
          auth       required     /lib/security/pam_pwdb.so shadow nullok
          auth       required     /lib/security/pam_shells.so
          account    required     /lib/security/pam_pwdb.so
          session    required     /lib/security/pam_pwdb.so