GNU libmicrohttpd is a small C library for embedding HTTP server functionality into other applications. It is reentrant, fast, supports HTTP 1.1, and permits listening on multiple ports. The API is simple and still powerful enough to allow programmers to use the entire HTTP feature set. SSL/TLS support is available as an option.
Hiawatha is a secure and advanced Web server for Unix. It has been written with security as its main goal. It features advanced access control, prevention of SQL injection and cross-site scripting, banning of clients who try such exploits, the ability to run CGIs under any UID/GID you want, and many other features. These features make Hiawatha an interesting Web server for those who need more security than what the other available Web servers are offering. Hiawatha is also fast and easy to configure.
DeleGate is a multi-purpose application level gateway or proxy server that mediates communication of various protocols, applying cache and conversion for mediated data, controlling access from clients, and routing toward servers. It translates protocols between clients and servers, converting between IPv4 and IPv6, applying SSL (TLS) to arbitrary protocols, merging several servers into a single server view with aliasing and filtering. It can be used as a simple origin server for some protocols (HTTP, FTP, and NNTP).
Cherokee is a very fast, flexible and easy to configure Web server. It supports widespread technologies including FastCGI, SCGI, uWSGI, PHP, CGI, SSI, TLS and SSL encrypted connections, virtual hosts, authentication, on the fly encoding, load balancing, Apache compatible log files, database balancing, reverse HTTP proxy, traffic shaping, video streaming, and much more. A user friendly interface called cherokee-admin is provided for no-hassle configuration of the server. It allows you to configure the server from top to bottom without editing a text configuration file.
Stunnix Advanced Web Server is a Web server for putting Web sites onto CD-ROMs, DVDs, FlashDisks, and other readonly media to be used on any typical system. Sites can be scripted with PHP, Python, Java, or Perl and can be driven by MySQL or SQLite databases. All required software programs are designed to reside on the CD-ROM to avoid the need to install software on the user's computer. The Web serving core is based on Apache 1.3.x, and has additional functionality to detect and use free ports and automatically start a browser on each platform. Desktop applications can also be created with it.
MatrixSSL is an embedded SSL and TLS implementation designed for small footprint devices and applications requiring low overhead per connection. The library is less than 50K on disk with cipher suites. It includes SSL and TLS client and server support, session resumption, and implementations of RSA, AES, 3DES, ARC4, SHA1, and MD5. The source is well documented and contains portability layers for additional operating systems, cipher suites, and cryptography providers.
CyaSSL is a C-language-based SSL library targeted for embedded and RTOS environments, primarily because of its small size and speed. CyaSSL supports the industry standards up to the current TLS 1.2 level, is up to 20 times smaller than OpenSSL, includes SSL client libraries and an SSL server implementation, includes an OpenSSL compatibility layer, and offers several progressive ciphers such as RABBIT and HC-128. Dual licensed under both the GPLv2 and standard commercial licensing, it caters to a wide range of projects.
Kannel is a WAP gateway. It attempts to provide this essential part of the WAP infrastructure freely to everyone so the market potential for WAP services, both from wireless operators and specialized service providers, will be realized as efficiently as possible. It also works as an SMS gateway for GSM networks. Almost all GSM phones can use it to send and receive SMS messages, so this is a way to serve many more clients than just those using a WAP phone. Kannel was among the first WAP gateways to be certified as WAP 1.1 compliant.