• OpenVPN
  OpenVPN is a full-featured SSL VPN solution which can accomodate a wide range of configurations, including remote access, site-to-site VPNs, WiFi security, and enterprise-scale remote access solutions with load balancing, failover, and fine-grained access-controls
  in Unix & Computing with openvpn vpn by 6 users
• Point to point client
  inux kernel 2.6.15 has been released and includes the PPP MPPE encryption module, which implements the Microsoft Point-to-Point Encryption method as a PPP compressor/decompressor.
  PPTP Client Project
  linux mppe pptp pptpd
  in Unix & Computing with privacy ssh tunnel vpn

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