The ilb utility executes a command on a machine chosen by the Network Load Balancer (NLB). To use the utility, enter the ilb(1) command followed by the command you want to execute. The NLB is queried to determine the machine to which you will be connected. After the login process is complete, the command is executed and I/O is connected to your terminal or pipeline. For information about using the ilb utility, see the ilb(1) man page.
Administration of ilb involves three main components, which affect the behavior of the ilb application. The components are as follows and are described in this chapter:
ilbrc file (requires a specific format)
$HOME/.ilbrc file (requires a specific format)
User's environment variables
The ilbrc file is located in the /nqebase/etc directory. There are two categories of information contained in the ilbrc file: LOGIN blocks and SYSTEM blocks.
LOGIN blocks are used to define login methods. These blocks start with a line containing LOGIN <name> and end with the line END LOGIN. There are three directives in the LOGIN block, USER, INVOKE, and SYS, which are described as follows:
| Directive | Description |
| USER | Specifies whether a line is to be input from (USER< ) or output to (USER>) the user's terminal. For example, the USER> directive indicates that the remainder of the line is printed to the user's terminal. The USER< directive must be followed by a temporary variable that indicates where the input will be stored. The USER_QUIET< directive is used for non-echoing input so that passwords are not visible when entered. |
| INVOKE | Specifies the application to be started to initiate a connection to a remote system. |
| SYS | Sends data to (SYS>) or receives data from ( SYS<) the remote system in order to complete the connection. |
The following three variables, which may be used in LOGIN blocks, are set automatically by the ilb utility:
| Variable | Description |
| $SYS | Stores the name of the system that was selected by the NLB for the session. |
| $USER | Stores the user name of the account to log into. The $USER variable is set with the -l option, or by reading the environment variables ILB_USER and LOGNAME or USER. |
| $PROMPT | Specifies a user's prompt; it contains a regular expression and may be changed by setting the environment variable ILB_PROMPT . |
SYSTEM blocks define options specific to machine names. The SYSTEM blocks begin with the line SYSTEM name; name is the name of a system or is DEFAULT to define the fallback case. The SYSTEM block ends with END SYSTEM.
The CONNECT attribute of the SYSTEM block defines which of the LOGIN blocks should be applied to a particular system.
The AVOID directive is placed outside of the LOGIN and SYSTEM blocks. It should be followed by a space-separated list of machine names; the ilb should not use these names. This is useful when a user or administrator wants to eliminate certain systems for use with the ilb.
Users may have their own ilb configuration files residing in their home directory. These configuration files are called .ilbrc. If this file is not present, the ilb uses the information contained in the system's ilbrc file. The format of this file is identical to that of the system's ilbrc file, which is defined in “ilbrc File”.
The user may also control the behavior of the ilb by defining the following specific environment variables.
 | Note:: The user may need to set up these variables if the default values do not work correctly. |
| Variable | Description |
| ILB_USER | Defines the login name to use on the remote system. This variable also alters the value of $USER in the ilbrc files. The default value is whatever $LOGNAME or $USER is set to be in the user's environment. |
| ILB_PROMPT | A regular expression that identifies the user's prompt on a remote machine. The default value is "^.*\[%$#:\] $", which looks for any string ending with %, $, #, or :. |
| NLB_SERVER | Defines the machine name and port number of the NLB server. |