pwnat, pronounced "poe-nat", is a tool that allows any number of clients behind NAT gateways to communicate with a server behind a separate NAT with no port forwarding and no DMZ setup on any routers in order to directly communicate with each other. The server does not need to know anything about the clients trying to connect, nor does it need to communicate with any other hosts in order to initiate the communication. Simply put, this is a proxy server that works behind a NAT, even when the client is behind a NAT. There is no middle man, no proxy, no third party, no UPnP required, no spoofing, and no DNS tricks. More importantly, the client can then connect to any host or port on any remote host or to a fixed host and port decided by the server.
Pagekite is software to make servers on "localhost" visible to the wider Internet. It can be used by Web developers to show off their works in progress to clients or colleagues, embedded developers who need direct access to devices in the field, or as an alternative to dynamic DNS for individuals/hobbyists who would rather host their own content than rely on 3rd party hosting. It creates and maintains a tunnel between your server on localhost and a remote "front-end" (a reverse proxy). Only the front-end has to have a visible IP address; the server itself can reside on a heavily firewalled computer, a mobile device, or even an anonymous node on the Tor network.
EARL is an HTTP tunneling proxy. It uses the POST method to transfer data. Since its datagrams are serialized objects, the traffic overhead is rather large. The datagrams are encrypted using AES to provide privacy and obfuscation to proxy maintainers. Inbound and outbound connections are possible. It is recommended to combine it with SOCKS proxies for a comfortable setup.
nassh-relay implements a relay server used with the Secure Shell (hterm) plugin for the Chromium Web browser. It tunnels ssh traffic through an HTTP xhr or websockets connection. It could be used as a gateway to route traffic to an internal network (it supports authentication on the HTTP endpoint) or simply as an ssh-over-HTTP proxy.
Hypersocket is a cross-platform Hybrid SSL VPN solution built for all types of remote access scenarios. Powerful, yet simple to use, Hypersocket uses a single installed client to provide access to any number of network resources. Its powerful granular access means you can have fine-grained control over your entire network and remote users. Accessed through a secure HTTPS port, the Hypersocket client provides access to any number of host/port combinations, all assigned server-side by the Administrator through roles. The Administrator is able to configure the server through a Web portal on the same HTTPS port.