I am experimenting an aplication to use pam for its authentication and was able to succesfully implement the support for PAM. Now,i am slightly confused by seeing different pam authentication modules. which one is most preferred pam module for authentication, pam_unix_auth or pam_unix2. Are there any differences between pam_unix_auth and pam_unix2. I came to know that pam_unix_auth can not support blowfish encryption for password. I could not find propoer information realted to this. Is pam_unix2 is the later version of pam_unix_auth? Any information in this regard will be greatly appreciated.