FTP over SSL

REF: http://www.proftpd.org/docs/howto/TLS.html

RFC 4217 defines FTP over SSL/TLS:

  http://www.faqs.org/rfcs/rfc4217.html

The mod_tls module for proftpd is an implementation of RFC 4217.
RFC 2228 defines FTP Security Extensions, of which mod_tls is one implementation. Another such RFC 2228 implementation is the mod_gssmodule, available from SourceForge.
Example mod_tls configuration:

  
    # If mod_tls was built as a shared/DSO module, load it
    LoadModule mod_tls.c