About CallingHome

CallingHome is a small and free tool that allows you to gain control over a firewalled und thus directly unreachable Windows PC (e.g your machine at work). It achieves this by establishing and maintaining a SSH connection from within the firewall to a SSH server of your choice. As the SSH protocol allows you to securely forward ports, this enables you to access any service (e.g. VNC, FTP etc.) available on the firewalled PC.

In principal, you can also achieve this by by starting a SSH session manually while sitting in front of the firewalled PC and leaving it running while moving outside the firewalled network. The problem with this approach is, that if for any reason the connection drops, you normally have no way to reactivate the SSH tunnel remotely. As it is very unlikely that you get a stable connection for more than a few hours and also the intendend SSH server (e.g. your router at home) may not always be reachable, this straight forward solution does not yield satisfactory results.

CallingHome solves this problem by actively maintaining a desired SSH connection and is able to provide a stable service without temporal limits. As the tool is actively monitoring the connection state, it's no problem if a connection "fall's asleep", just drop's or the SSH server get's temporarily unreachable. CallingHome will simply reestablish the connection as soon as possible.

Additional Info

• This project is not related to the site CallingHome.biz and has nothing to do with spyware or similar annoyances.
• You do not need to have administrator-rights to install/use CallingHome.
• As PuTTY is even able to create a connection through HTTP proxies, the concept works for nearly every firewalled PC out now.
• Thanks to SSH, all communication is secured by strong and trustworthy encryption.
• As keyboard-interactive authentication is not possible, RSA-key authentication should be used instead of storing your password in the PuTTY session.

Contact

If you have any questions or want to provide some feedback, you may contact me by sending an e-mail to <callinghome (at) plattner.ws>.