msmtp is an SMTP client with a sendmail compatible interface. It can be used with Mutt and other MUAs. It forwards messages to an SMTP server which does the delivery. Features include various SMTP AUTH methods, TLS/SSL-encrypted connections (including support for client certificates), support for multiple accounts, DSN, and IPv6 support.
Ctalk adds classes, methods, operator overloading, inheritance, and complex object expressions to otherwise standard C programs. Programs can use only a few Ctalk objects and methods in an otherwise standard C program, but the language can be used to write entire programs also. Ctalk works on most if not all of the systems that support GCC, the GNU C compiler. The package includes the language, class and run-time libraries, example programs, tutorial, and language reference.
getmail is intended as a simple, secure, and reliable replacement for fetchmail. It retrieves email (either all messages, or only unread messages) from one or more POP3, SPDS, or IMAP4 servers (with or without SSL) for one or more email accounts, and reliably delivers into qmail-style Maildirs, mboxrd files, or through external MDAs (command deliveries) specified on a per-account basis. getmail also has excellent support for domain (multidrop) mailboxes, including delivering messages to different users or destinations based on the envelope recipient address.