Advanced Client Use (SSH, The Secure Shell: The Definitive Guide)

16.4. Advanced Client Use

To establish an SSH connection, you must fill in the following Connection fields in the Properties window. These include:

Host Name: The name of the remote SSH server machine to which you want to connect.
User Name: Your username on the remote SSH server machine. If you're using public key (RSA) authentication, this username must belong to an account that contains your public key.
Port Number: The TCP port for SSH connections. Virtually all SSH clients and servers operate on port 22. Unless you plan to connect to a nonstandard SSH server, you don't need to change this. [Section 7.4.4.1, "Selecting a remote port"]
SSH Protocol: You may require SSH-1 or SSH-2, or select Automatic to let the program figure it out based on the server's response.

Optionally, you may select the encryption cipher and an authentication method. In the Properties window, select Cipher to choose the set of encryption ciphers you will permit your client to use. (The default should be acceptable for most uses.) The SSH server negotiates with your client to choose a cipher they both support.

Your authentication method can be public key or password, which may be chosen in the login window. The program automatically tries to authenticate with each of your User Keys in order. [Section 16.3.4, "Using Keys"]

16.4.1. Data Compression

F-Secure SSH can transparently compress and uncompress the data traveling over an SSH connection, which can speed up your connection. [Section 7.4.11, "Data Compression"]

In the Properties window, choose Connection, and check the box labeled Compression. There's no way to set different compression levels as in SSH1.

16.4.2. Debugging with Verbose Mode

Is your SSH session not working as expected? Turn on verbose mode so status messages are printed in the window as your session runs. This can help you locate and solve problems.

In the Properties window, select Appearance and check the box labeled Verbose Mode. The next time you connect, you'll see messages like this:

debug: connecting ...
debug: addresses 219.243.169.50
debug: Registered connecting socket: 12
debug: Connection still in progress
debug: Marked name resolver 1 killed
debug: Replaced connected socket object 12 with a stream

Verbose mode is much like its counterpart in the Unix SSH products. [Section 7.4.15, "Logging and Debugging"] It can be an indispensable tool for diagnosing problems with your connection.

16.4.3. SOCKS Proxy Server

F-Secure SSH Client supports connecting through SOCKS Version 4 proxy servers. [Section 4.1.5.8, "SOCKS proxy support"] On the Properties window, select Socks and fill in the hostname or IP address of the proxy server machine and the port number on the proxy (the usual SOCKS port is 1080).

16.4.4. Accepting Host Keys

Every SSH server has a unique host key that represents the server's identity, so SSH clients can verify that they are speaking with the actual server and not an impostor. [Section 2.3.1, "Known Hosts"] F-Secure SSH Client keeps track of all host keys it encounters. The keys are stored in the Windows registry.

If you want F-Secure SSH Client to reject host keys it hasn't seen before, visit the Properties window and select Security. A checkbox is available to set this option.

Some of the Unix command-line options aren't supported. Type the program name by itself (e.g., ssh2 ) to see the current list of options.
Key files aren't supported; these programs read keys from the Windows registry, just as F-Secure SSH Client does.

The command-line programs are useful for scripting and batch files, or for executing remote commands on the server machine:

C:\> ssh2 server.example.com mycommand

16.4. Advanced Client Use

16.4.1. Data Compression

16.4.2. Debugging with Verbose Mode

16.4.3. SOCKS Proxy Server

16.4.4. Accepting Host Keys

16.4.5. Additional Security Features

16.4.6. Secure File Transfer with SFTP

16.4.7. Command-Line Tools