System Management Guide: Communications and Networks

Configuring BNU

The following procedures detail how to configure Basic Network Utilities (BNU) for various types of connections, including hardwired, modem, and Transmission Control Protocol/Internet Protocol (TCP/IP) connections.

Prerequisites

BNU must be installed on your system.
You must have root user authority to edit the BNU configuration files.
If you are using direct connections for BNU communications, the appropriate hardwired connections between your system and the remote systems must be set up.
If you are using modems for BNU communications, you must have installed and configured each modem.
If one or more of your connections uses TCP/IP, then TCP/IP must be running between your system and the apropriate remote systems.
Collect the information you need to configure BNU. This information should include a list of remote systems and lists of devices and modems to use to connect to the systems.

Information to Collect before Configuring BNU

Before configuring BNU, gather the information listed:

For each remote system your system will call, collect the following information:
- System name
- Login name your system should use on the remote system
- Password for the login name
- Login and password prompts on the remote system
- Type of connection you will use to reach the remote system (TCP/IP, direct, or telephone).
If the connection is direct, collect:
- The bit rate of the connection
- The port on the local system to which the connection is attached.
If the connection is a telephone connection, collect:
- The telephone number of the remote system
- The speed of your modem that is compatible with that of the remote system.

Note: If any of the remote systems will call your system, ensure the BNU administrator on each of the remote systems has all the preceding information about your system.

For each local modem that you will use for BNU connections, collect the following information:
- The chat script for the modem (consult the modem documentation)
  
  Note: For some modems, the chat script is already in the /etc/uucp/Dialers file.
- The local port for the modem.

Using the information you collect, make a list of each device you need to connect to a remote system. Following is a sample list for local system morgan:

direct:
hera 9600 tty5
zeus& 2400 tty2
ariadne 2400 tty1
hayes modem (tty3):  apollo, athena
TCP/IP:  merlin, arthur, percy

To connect to system hera, a direct connection at a speed of 9600 from port tty5 is used. To connect to system apollo, the hayes modem connected to port tty3 is used. TCP/IP is used to connect to systems merlin, arthur, and percy.

Procedure

For BNU to function correctly at your site, you must configure the remote communications facilities to:

List the devices used to establish a hardwired, telephone, or modem communications link.
List the modems used to contact remote systems over the telephone network.
List the accessible remote systems.
List the alphabetic abbreviations representing the prefixes of telephone numbers used to contact the specified remote systems (optional).
Set access permissions specifying the ways in which local and remote systems may communicate.
Schedule monitoring for the networked remote systems (optional).

To create these lists, permissions, schedules, and procedures:

Modify the BNU configuration files.
Edit the /var/spool/cron/crontabs/uucp file to remove the comment characters (#) from the beginnings of the lines that schedule the automatic maintenance routines.

You must configure the Systems, Devices, and Permissions files before BNU will run correctly at your site. However, it is not necessary to modify the BNU configuration files in any particular order.

To configure BNU on your system:

Make sure that BNU is installed on your system by running the command:
```
lslpp -h bos.net.uucp
```
If BNU is installed, you will see bos.net.uucp in the output. If you do not see it, install it from the install tape.
Set up appropriate login IDs and passwords for remote systems that will call your system, and tell the person responsible for administering BNU or UNIX-to-UNIX Copy Program (UUCP) on each remote system the login and password you have provided. This is done by editing the /etc/passwd, /etc/group, /etc/security/login.cfg, and /etc/security/passwd files.

Attention: Allowing remote systems to log into the local system with the UUCP login ID seriously jeopardizes the security of your system. Remote systems logged in with the UUCP ID can display and possibly modify (depending on the permissions specified in the LOGNAME entry of the Permissions file) the local Systems and Permissions files. It is strongly recommended that you create other BNU login IDs for remote systems and reserve the uucp login ID for the person administering BNU on the local system. For the best security, each remote system that contacts the local system should a have unique login ID with a unique UID number. These login IDs should have GIDs of 5. By default, the operating system includes the nuucp login ID for transferring files.
1. You have the option of maintaining separate logins or having one login for all BNU connections. If you need to maintain complete control over access by each individual machine, you must create separate login IDs, as well as combine the MACHINE and LOGNAME entries in the Permissions file. A few example /etc/passwd entries are shown here:
```
Umicrtk:!:105:5:micrtk uucp:/usr/spool/uucppublic:/usr/sbin/uucp/uucico
Ufloydl:!:106:5:floydl uucp:/usr/spool/uucppublic:/usr/sbin/uucp/uucico
Uicus:!:107:5:icus uucp:/usr/spool/uucppublic:/usr/sbin/uucp/uucico
Urisctkr:!:108:5::/usr/spool/uucppublic:/usr/sbin/uucp/uucico
```
2. If you want to have one set of permissions and do not want to maintain separate control for any of your UUCP connections, you can have a single login for all machines such as the following:
```
nuucp:!:6:5::/usr/spool/uucppublic:/usr/sbin/uucp/uucico
```
3. The user ID (the third colon separated field) must be unique to avoid a security risk. The group ID (the fourth separated field) must be 5, the same group as uucp. You can change the home directory (the sixth field) to any valid directory, but the login shell (the seventh field) must be /usr/sbin/uucp/uucico.
4. Make sure that the /etc/group file contains the new users. An example of such an entry is:
```
uucp:!:5:uucp,uucpadm,nuucp,Umicrtk,Uicus,Urisctakr
```
5. You may want to add any users to group uucp who will be using modems to dial out with programs other than the cu command.
6. After editing these files as root, set up a password for the new users with the command passwd UserName.
7. Sometimes, the default herald with all of its Ctrl-J's, will cause a uucico process that is trying to login to give up. (You may see the message Enough already.) You can avoid that by commenting out (with asterisks) the default stanza, and defining a stanza for your tty something like this:
```
 /dev/tty0:
             herald = "\nrisc001 login:"
```
8. If you change a password from the root login, the flags entry in the stanza for the user in /etc/security/passwd will contain the following:
```
flags = ADMCHG                                 
```
  Change it to:
```
flags =
```
  Otherwise, when the remote uucico logs in, it will be prompted to enter a new password, which it cannot do. Hence the login will fail.
9. Using an ASCII text editor or the uucpadm command, edit the Poll file. Add an entry for each system your system will poll.
  
  Note: The systems listed in the Poll file must also be listed in the /etc/uucp/Systems file.
10. Using an ASCII text editor, edit the /var/spool/cron/crontabs/uucp file. Remove the comment characters (#) from the lines that run the uudemon.hour and uudemon.poll commands. You can change the times these commands are run. However, be sure to schedule the uudemon.poll command approximately five minutes before you schedule the uudemon.hour command.
11. Check to make sure your changes took effect by running this command:
```
crontab -l
```
12. Set up the `BNU data files: Systems, Permissions, Devices, Dialers, and Sysfiles. You could use the /usr/sbin/uucp/uucpadm command to initially set up the files and then edit them to suit your exact needs. Note that the Sysfiles file allows you to specify files other than /etc/uucp/Systems, /etc/uucp/Devices, and /etc/uucp/Dialers for BNU configuration. See Sysfiles for more information.
Decide whether to use dial-code abbreviations for telephone numbers (see the Dialcodes file format). If you decide to use dial-code abbreviations in the Systems files, set up the Dialcodes entry for each abbreviation. Refer to Dialcodes File Format for BNU in AIX 5L Version 5.1 Files Reference for details.
If you are using TCP/IP for your BNU connections, use the netstat command to see whether the uucpd daemon is runnable, by entering:
```
netstat -a
```
The uucpd daemon is started by the inetd daemon. If the uucpd daemon is not able to run, reconfigure the inetd daemon to start the uucpd daemon.
Using the list of devices you collected before beginning this procedure, modify the Devices file on your system. Make an entry for each modem and each direct connection. If you are using TCP/IP, make sure you uncomment the TCP/IP entry in the Devices file. You can configure the /etc/uucp/Sysfiles file to specify other files to use for Devices configuration. Refer to the Devices File Format for BNU in AIX 5L Version 5.1 Files Reference for details on the Devices file. Refer to Sysfiles File Format for BNU for details on the Sysfiles file in AIX 5L Version 5.1 Files Reference.
Also, if you are using TCP/IP, check to see whether the /etc/services file includes:
```
uucp        540/tcp          uucpd
```
If not, add the line.
Using your information about each remote system that you collected before beginning this procedure, modify the Systems file on your system. Use the commented examples in the Systems file as a guide when specifying your configuration. See the "BNU Systems File Format" in AIX 5L Version 5.1 Files Reference for details. If you are using TCP/IP, ensure the host-name table in the /etc/hosts file includes the name of the remote computer with which you want to connect. You can configure the /etc/uucp/Sysfiles file to specify other files to use for Systems configuration. Refer to Sysfiles File Format for BNU in AIX 5L Version 5.1 Files Reference for more information.
Using the information about devices and modems that you collected before beginning this procedure, make sure the Dialers file on your system contains an entry for each modem. If you are using TCP/IP and direct connections, make sure the TCP/IP entry and direct entries are present in the file. Refer to Dialers File Format for BNU in AIX 5L Version 5.1 Files Reference for details. You can configure the /etc/uucp/Sysfiles file to specify other files to use for Dialers configuration. Refer to Sysfiles File Format for BNU in AIX 5L Version 5.1 Files Reference for more information.
Decide how much access to your system you want to provide to each remote system you call and to each remote system that calls you. Set up appropriate entries for each system and each login name in the Permissions file. Refer to Permissions File Format for BNU in AIX 5L Version 5.1 Files Reference for details.
Issue the uucheck command to verify that everything is in place:
```
/usr/sbin/uucp/uucheck -v
```
The uucheck command verifies that the directories, programs, and support files are set up properly and that the Permissions file entries are consistent. If the uucheck command reports any errors, fix the errors.
If you wish, set up automatic monitoring of BNU operations and automatic polling of remote systems.

Setting Up Automatic Monitoring of BNU

Prerequisites

Complete the steps in Configuring BNU.
You must have root user authority to edit the /var/spool/cron/crontabs/uucp file.

Procedure

BNU uses the cron daemon to start BNU daemons and to monitor BNU activity. The cron daemon reads the /var/spool/cron/crontabs/uucp file for instructions about when to start BNU procedures.

Log in as a user with root user authority.
Using an ASCII text editor, edit the /var/spool/cron/crontabs/uucp file.
Uncomment the lines for the BNU maintenance procedures, uudemon.admin and uudemon.cleanup. You can change the times these procedures are run if your system needs maintenance at more or less frequent intervals. It is best, however, to run the uudemon.admin command at least once a day and the uudemon.cleanup command at least once a week.
You can use the crontabs/uucp file to schedule other BNU maintenance commands, such as the uulog, uuclean, or uucleanup commands. In addition, you can use the crontabs/uucp file to instruct the cron daemon to start the uucico, uuxqt, or uusched daemons at specific times.

Setting Up BNU Polling of Remote Systems

Prerequisites

Complete the steps in Configuring BNU.
You must have root authority to edit the /var/spool/cron/crontabs/uucp file and the /etc/uucp/Poll file.

Procedure

To enable BNU to poll remote systems for jobs, list the systems in the /etc/uucp/Poll file. In addition, run the uudemon.hour and uudemon.poll commands periodically.

Decide which remote systems to automatically poll. Decide how often you want to poll each one. Specify times for each system with the Poll file as seldom as once a day or as often as you wish.
Log in as a user with root authority.
Using an ASCII text editor or the uucpadm command, edit the Poll file. Add an entry for each system your system will poll.

Note: The systems listed in the Poll file must also be listed in the /etc/uucp/Systems file.
Using an ASCII text editor, edit the /var/spool/cron/crontabs/uucp file. Remove the comment characters (#) from the lines that run the uudemon.hour and uudemon.poll commands. You can change the times these commands are run. However, be sure to schedule the uudemon.poll command approximately five minutes before you schedule the uudemon.hour command.

BNU will now automatically poll the systems listed in the Poll file at the times you have specified.

Using the /etc/uucp/Systems File

The remote systems are listed in the /etc/uucp/Systems files. The /etc/uucp/Systems file is the default Systems file. The system administrator can specify additional files in the /etc/uucp/Sysfiles file.

Each entry in a Systems file contains:

Name of the remote system
Times when users can connect to the remote system
Type of link (direct line or modem)
Speed of transmission over the link
Information needed to log in to the remote system.

Each entry in a Systems file represents one remote system. To establish communications, the remote system must be listed in the local Systems file. A Systems file must be present on every system that uses the BNU facility. Normally, only the root user can read the Systems files. Any user, however, can list the names of remote BNU systems using the uuname command.

Editing Devices Files for Hardwired Connections

Prerequisites

You must have root authority to edit the /etc/uucp/Devices file or another file specified in /etc/uucp/Sysfiles as a Devices file.

Procedure to Set Up a System Name Entry

To set up a hardwired connection specifying a port and a remote system, make an entry as follows:

Enter the name of the remote system to which you want to connect the local computer over the hardwired line in the Type field in the second line of the entry.
Enter the device name appropriate for the hardwired connection used at your site in the Line field in both lines of the entry.
Enter a - (hyphen) for a placeholder in the Line2 field in both lines of the entry.
Enter the transmission rate appropriate for the hardwired connection used at your site in the Speed field in both lines of the entry.
Enter direct (all lowercase) in the Dialer-Token Pairs field in both lines of the entry.

For example:

type device - speed direct

Continue adding entries to the Devices file until you have listed each hardwired device connecting the local system to a remote system.

Procedure to Set Up a Direct Entry

To set up a hardwired connection between two systems that use a permanent asynchronous serial connection, make a one-line entry as follows:

Enter the name of the remote system in the first (Type) field.
Enter the name of the tty device in the second (Line) field.
Enter a - (hyphen) for a placeholder in the third (Line2) field.
Enter the transmission rate appropriate for the hardwired connection used at your site in the fourth (Class) field.
Enter direct (all lowercase) in the fifth (Dialer-Token Pairs) field.

For example:

type device - speed direct

Continue adding entries to the Devices file until you have listed each hardwired device connecting the local system to a remote system.

Editing Devices File for Autodialer Connection

Prerequisites

You must have root authority to edit the /etc/uucp/Devices file or another file specified in /etc/uucp/Sysfiles as a Devices file.

Procedure

In telephone-connection entries, the Type field is specified as an automatic calling unit (ACU). Type ACU as the Type field entry in all remote connections established over a phone line. To set up Device file entries for autodialer connections, make a one-line entry for each modem:

Enter ACU in the first (Type) field.
The second (Line) field contains the name of the device that is attached to the modem. Enter the device name appropriate for your site.
Enter a - (hyphen) as a placeholder in the third (Line2) field, unless the autodialer is a standard 801 dialer. If the autodialer is a standard 801 dialer, enter 801.
In the fourth (Speed) field, enter the baud rate appropriate for your modem and line (this can be 300, 1200, 2400, or higher, depending on the modem) or the class of your modem (for example, D2400).

Note: If the modem can be used at more than one specific rate, make a separate entry in the Devices file for each rate. If the modem can be used at any rate, enter the word Any in the Speed field.
Enter the name of the modem as the Dialer field entry in the fifth (Dialer-Token Pair) field. If you are planning to include complete phone numbers in the /etc/uucp/Systems file or another Systems file specifies in /etc/uucpSysfiles, leave the Token field blank. (A blank instructs the BNU program to use the default \D token.) If you are planning to use dialing-code abbreviations specified in the /etc/uucp/Dialcodes file, enter the token \T.

For example:

type line - speed dialer - token pair

Continue adding entries to the Devices file until you have listed each connection between the local system and a remote system that uses a telephone line and a modem.

TCP - - - TCP