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

15.4. Advanced Client Use

SecureCRT lets you change settings for its SSH features and its terminal features. We will cover only the SSH-related ones. The others (and more details on the SSH features) are found in SecureCRT's online help.

SecureCRT calls a set of configuration parameters a session. It also distinguishes between session options that affect only the current session and global options that affect all sessions.

You can change session options before starting an SSH connection or while you are connected. Some options can't be changed while connected, naturally, such as the name of the remote SSH server machine. View the Session Options window (Figure 15-1) by selecting Session Options from the Options menu or clicking the Properties button on the button bar.

15.4.1. Mandatory Fields

To establish any SSH connection, you must fill in all the Connection fields in the Session Options window. These include:

Name: A memorable name for your collection of settings. This can be anything, but it defaults to the name of the SSH server.
Protocol: Either SSH-1 or SSH-2.
Hostname: The name of the remote SSH server machine to which you want to connect.
Port: 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 won't need to change this. [Section 7.4.4.1, "Selecting a remote port"]
Username: 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.
Cipher: The encryption algorithm to be used. Unless you have strong feelings about ciphers, use the default (3DES).
Authentication: How you identify yourself to the SSH server. This can be password authentication (using your remote login password), RSA authentication (public key), or TIS. [Section 15.4.3, "TIS Authentication"] Trusted-host authentication isn't supported.

15.4.2. Data Compression

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

In the Session Options window, choose Connection, and click the Advanced button and the General tab. The checkbox "Use Compression" enables data compression. You may also set a value for Compression Level. Its function is identical to the CompressionLevel keyword of SSH1. The higher the value, the better the compression, but the greater load on the CPU, potentially slowing your computer.

15.4.3. TIS Authentication

SecureCRT can authenticate you via the Gauntlet firewall toolkit from Trusted Information Systems (TIS). [Section 5.5.1.8, "TIS authentication"] In the Session Options window, under Connection, simply set Authentication to TIS.

15.4.4. Firewall Use

SecureCRT supports connections through several types of firewalls, such as the SOCKS4 and SOCKS5 firewalls supported by the SSH1 and SSH2 servers. Visit the Global Options window, select Firewall, and fill in the requested fields. You need to know the hostname or IP address of the firewall, and the TCP port on which to connect.