Qpopper 4.1a5

Qpopper project is the most widely-used server for the POP3 protocol (this allows users to access their mail using any POP3 client). Qpopper supports the latest standards, and includes a large number of optional features. Qpopper is normally used with standard UNIX mail transfer and delivery agents such as sendmail or smail.
Qpoppers goals are: security, stability, safety, features, and performance.
The 3 and later code base has multiple levels of protection again common security vulnerabilities, so even if there is a bug at one level, the other levels can protect against an exploit. Stability means running without crashing or other problems. All bug reports are reviewed and taken seriously.
Safety means protecting the users mail. Qpopper takes extra precautions to guard against spool corruption, even if there is a system crash or power failure during an update. Qpopper provides a large number of features, such as bulletins, support for wireless devices, APOP, integration with packages such as Kerberos, drac, etc.
Qpopper strives for the maximum possible performance consistent with safety. You can also tell Qpopper when it is running in an environment where some precautions are not required, resulting in extra performance (for example, if users do not access mail using shell accounts).
This server is fully compliant with RFC 1939 (which defines the POP protocol) and RFC 2449 (which defines the POP extension mechanism and the extended response codes), and works with all known POP3 clients.
Qpopper also supports Kerberos V4 and V5 if enabled.
Main features:
- Faster start-up (1,000 times faster, in many cases)
- Reduced I/O at session end (one-third less!)
- TLS/SSL (allows authentication and email to be strongly encrypted between any TLS/SSL-enabled mail client and Qpopper 4.0.5; requires TLS/SSL)
- Plus all the great features of Qpopper 3.1 (including full sources)
- Most compile-time options now are available at run-time
- Easier administration