> - encrypted filesystem > - SSL or TLS only for SMTP and IMAPS > - Talking only to some known other same-secured servers > *Thank you for any infos*
If you really need security, do not forget to use a safe source for your mailrouting information (e.g. ipaddresses or *really* secured dns - do not rely on simple mx lookups). If you own the complete setup (all involved machines): Use clientcertificates (works also for servers ;)) and verified TLS (postfix level "secure"). Create an internal CA that issues all involved certificates (>=2048bit) and do only set up trust for that one (no other CA). Cheers, Jan