Polipo - A small and fast caching web proxy (a web cache, an HTTP proxy, a proxy server).
Hamachi - Hamachi is a VPN service scaled to the unique needs of business owners.
Artica Proxy - Artica Proxy is an appliance that claim to manage Squid-cache proxy with all features that Squid...
ZeroTier - Extremely simple P2P Encrypted VPN
Privoxy - Privoxy helps users to protect their privacy.
OpenVPN - OpenVPN - The Open Source VPN