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### 4.17 Issues with Cygwin ssh

This section needs a lot of work! Please help.

The recent Cygwin installation of `ssh` works only with a Cygwinized GNU Emacs. You can check it by typing `M-x eshell`, and starting `ssh test.machine`. The problem is evident if you see a message like this:

         Pseudo-terminal will not be allocated because stdin is not a terminal.

Older `ssh` versions of Cygwin are told to cooperate with tramp selecting `sshx` as the connection method. You can find information about setting up Cygwin in their FAQ at http://cygwin.com/faq/.

If you wish to use the `scpx` connection method, then you might have the problem that GNU Emacs calls `scp` with a Windows filename such as `c:/foo`. The Cygwin version of `scp` does not know about Windows filenames and interprets this as a remote filename on the host `c`.

One possible workaround is to write a wrapper script for `scp` which converts the Windows filename to a Cygwinized filename.

If you want to use either `ssh` based method on Windows, then you might encounter problems with `ssh-agent`. Using this program, you can avoid typing the pass-phrase every time you log in. However, if you start GNU Emacs from a desktop shortcut, then the environment variable `SSH_AUTH_SOCK` is not set and so GNU Emacs and thus tramp and thus `ssh` and `scp` started from tramp cannot communicate with `ssh-agent`. It works better to start GNU Emacs from the shell.

If anyone knows how to start `ssh-agent` under Windows in such a way that desktop shortcuts can profit, please holler. I don't really know anything at all about Windows...