Progressive technologies deployed by unstable.nl

SPF records and checking: unstable.nl is already checking SPF records of incoming mail. As of February 9th 2005 SPF records for unstable.nl will also be published in the DNS, so that other mail servers will be able to detect forgery of the unstable.nl domain.
Blowfish hashed passwords: unstable.nl stores user passwords with one-way blowfish hashes. This is provided by pam_unix2, a PAM module, available as Debian package "libpam-unix2". The nice thing about this module is that it is backwards compatible with MD5 passwords, so users aren't forced to change their passwords.
SFS: self-certifying fliesystem: SFS wraps around NFS and provides strong encryption and authentication. Notable features are SRP authentication, which not only authenticates the user to the server, but also vice versa! This prevents man-in-the-middle attacks. The self-certifying feature also prevents such attacks by embedding the fingerprint of the server's certificate in the address of the resource you want to access.