Stunnel – proxy designed to add TLS encryption functionality

Stunnel is a program that allows you to encrypt arbitrary TCP connections inside SSL (Secure Sockets Layer).

Stunnel can allow you to secure non-SSL aware daemons and protocols (like POP, IMAP, LDAP, etc) by having Stunnel provide the encryption, requiring no changes to the daemon’s code.

Stunnel does not contain any cryptographic code itself — instead it relies on external SSL libraries.

Features include:

• Being an SSL client.
• Being an SSL server.
• Server and client side certificate verification.
• TCP wrapper support.
• IDENT lookups.
• SMTP protocol negotiation.
• Source address rewriting (transparency) (where supported by the OS).
• Restricting allowed SSL ciphers.

Website: www.stunnel.org
Support: FAQ
Developer: Michal Trojnara and contributors
License: GNU General Public License v2.0

Stunnel is written in C. Learn C with our recommended free books and free tutorials.

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