DeskNow WebMessenger is a Jabber/XMPP secure instant messaging server that includes a Web-based IM client. It can be accessed transparently across firewalls, proxies, and NAT, and supports 128-bit SSL encryption. Other features include the support for unlimited virtual domains, a Web-based administration console, and the ability to send broadcast messages and alerts to all users. It is compatible with the most popular Jabber clients, and can run on any OS.
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.