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AIX Version 4.3 System Management Guide: Communications and Networks

BNU Configuration Files

Basic Network Utilities (BNU) uses the following configuration files:

/etc/uucp Contains all the configuration files for BNU.
/var/spool/uucppublic Contains files that have been transferred.
/etc/uucp/Systems Contains a list of systems to which the uucico program can connect.
/etc/uucp/Devices Defines the device type, location, speed, and other basic communication parameters for many system dial-out programs. Only dial-out connections use this file.
/etc/uucp/Permissions Creates security control, with limitations, over machines attempting to communication with your machine.
/etc/uucp/Dialers Specifies the dialer types. Each dialer uses a specific command set when attempting to dial the modem. The most common dialer types are hayes , direct , and TCP (Transmission Control Protocol).
/etc/uucp/Dialcodes Makes standardized names for certain parts of a phone number. For example, if you frequently make calls to a certain area code in San Francisco, you could create the following entry: SF09,1415 .
/etc/uucp/Sysfiles Enables a BNU administrator to specify files to fill the role of BNU configuration files other than /etc/uucp/Systems, /etc/uucp/Devices and /etc/uucp/Dialers. Distinctions can be made between what files are used for uucico traffic versus cu-related (cu, ct, slattach) activity.
/usr/sbin/uucp/remote.unknown Defines a shell script. It is run by the BNU program when a remote computer that is not listed in the local permissions file attempts to communicate with that local system.
/etc/uucp/Poll Schedules polling of passing systems. Its format is similar to the crontab file. Poll format is SiteName, a tab, and the hours to poll (0-23), separated by spaces.

Correlation of Files

Systems file: SystemName Any v32ibm 9600 555-1111
Devices file: v32ibm tty0 - Any ibm \D
Dialers file: ibm =, -, #" \d ATSFI\r\c#OK#AFE1SD3L2MIC0SCI\r\c#OK...

BNU Configuration for a TCP/IP Connection Example

The following files are set up for a Transmission Control Protocol/Internet Protocol (TCP/IP) connection between systems zeus and hera , where zeus is considered the local system and hera the remote system.

Entries in the Local System's Files

Files containing telephone connection entries on local system venus include the following:

Systems File

The Systems file on system zeus should contain the following entry to allow zeus to contact system hera :

hera Any TCP,t - - in:--in: uzeus word: birthday

This specifies that system zeus can call system hera at any time, using the t protocol for communications with system hera . System zeus logs in to system hera as uzeus with the password birthday .

Note: The t protocol supports the tcp protocol. Therefore, always use the t protocol for BNU communications over TCP/IP connections. However, the t protocol cannot be used when the Type field is ACU (automatic calling unit) or when a modem connection is being used.

BNU uses the Type and Class fields in the Systems file to find the appropriate device for the connection. Accordingly, it checks the Devices file for an entry of type TCP .

Devices File

A Devices file used by uucico on system zeus should contain the following entry for TCP/IP connections:

TCP  -  -  -  TCP

Because the device type is TCP , there are no Class, Line, or Line2 entries. The Dialer is also specified as TCP . Accordingly, BNU looks in the Dialers files for a TCP entry.

Dialers File

The Dialers file used by uucico on system zeus should contain a TCP/IP entry as follows:

TCP

This entry specifies that no dialer configuration is required.

Note: Dialer configuration is never required over a TCP/IP connection.
Permissions File

The Permissions file on system zeus contains the following entry specifying system hera 's access to system zeus :

LOGNAME=uhera SENDFILES=yes REQUEST=yes \
MACHINE=zeus:hera VALIDATE=uhera /
READ=/var/spool/uucppublic:/home/hera \
WRITE=/var/spool/uucppublic:/home/hera COMMANDS=ALL

This combined LOGNAME and MACHINE entry provides the following permissions to system hera on system zeus :

Entries in the Remote System's Files

Files containing telephone connection entries on remote system merlin include the following.

Systems File

A Systems file on system hera should contain the following entry to allow hera to contact system zeus :

zeus Any TCP,t - - ogin:--ogin: uhera ord: lightning

This specifies that system hera can call system zeus at any time, using the t protocol for communications with system zeus . System hera logs in to system zeus as user uhera with the password lightning . Again, BNU next checks the Devices files for an entry of type TCP .

Note: The t protocol supports the tcp protocol. Therefore, always use the t protocol for BNU communications over TCP/IP connections. However, the t protocol cannot be used when the Type field is ACU or when a modem connection is being used.
Devices File

The Devices file used by uucico on system hera should contain the following entry for TCP/IP connections:

TCP  -  -  -  TCP

Because the device type is TCP , there are no Class, Line, or Line2 entries. The Dialer is also specified as TCP . Accordingly, BNU looks in the Dialers files for a TCP entry.

Dialers File

The Dialers file used by uucico on system hera should contain a TCP/IP entry as follows:

TCP

This entry specifies that no dialer configuration is required.

Note: Dialer configuration is never required over a TCP/IP connection.
Permissions File

The Permissions file on system hera contains the following entry specifying system zeus 's access to system hera :

LOGNAME=uzeus SENDFILES=yes REQUEST=yes \
MACHINE=hera:zeus VALIDATE=zeus COMMANDS=rmail:who:uucp

This combined LOGNAME and MACHINE entry provides the following permissions to system zeus on system hera :

BNU Configuration for a Telephone Connection Example

The following sample files are set up to connect systems venus and merlin over a telephone line using modems. System venus is considered the local system and system merlin the remote system.

On both systems, the device tty1 is hooked to a Hayes modem at 1200 baud. The login ID used for system venus to log into system merlin is uvenus , and the associated password is mirror . The login ID for system merlin to log into system venus is umerlin , and the associated password is oaktree . The phone number for the modem attached to venus is 9=3251436 ; the number of the merlin modem is 9=4458784 . Both computers include partial phone numbers in their Systems files and dial-codes in their Dialcodes files.

Entries on the Local System

Files containing telephone connection entries on local system venus include the following.

Systems File

The Systems file on venus should contain the following entry for merlin , including a phone number and a dialing prefix:

merlin Any ACU 1200 local8784 "" in:--in: uvenus word: mirror

System venus can call system merlin at any time, using an ACU device at 1200 baud and logging in as uvenus with the password mirror . The telephone number is expanded based on the code local in the Dialcodes file, and the device to be used is determined based on the Type and Class entries. Accordingly, BNU checks the Devices files for a device of type ACU and class 1200 .

Dialcodes File

The Dialcodes file on system venus contains the following dial-code prefix for use with the number in the Systems file:

local 9=445

Given this code, the telephone number for system merlin in the Systems file is expanded to 9=4458784 .

Devices File

The Devices file on system venus should contain the following entry for the connection to system merlin :

ACU tty1  -  1200  hayes \T

The port to be used is tty1 , and the Dialer entry in the Dialer-Token Pairs field is hayes . The Token entry, \T , indicates that the telephone number is to be expanded using a code from the Dialcodes file. BNU checks the Dialers files for a hayes dialer type.

Dialers File

A Dialers file used by uucico on system venus should contain the following entry for the hayes modem:

hayes =,-, "" \dAT\r\c OK \pATDT\T\r\c CONNECT
Note: The expect-send characters are defined in the Dialers file format.
Permissions File

The Permissions file on system venus contains the following entries specifying the ways in which system merlin can conduct uucico and uuxqt transactions with system venus :

LOGNAME=umerlin REQUEST=yes SENDFILES=yes \
READ=/var/spool/uucppublic:/home/merlin \
WRITE=/var/spool/uucppublic:/home/merlin
MACHINE=venus:merlin VALIDATE=umerlin REQUEST=yes SENDFILES=yes    \
COMMANDS=ALL \
READ=/var/spool/uucppublic:/home/merlin \
WRITE=/var/spool/uucppublic:/home/merlin

System merlin logs in to system venus as umerlin , which is a unique login for system merlin . It can request and send files regardless of who initiated the call. Also, system merlin can read and write to the /var/spool/uucppublic directory and the /home/merlin directory on system venus . It can issue all commands in the default command set on system venus .

Entries on the Remote System

Files containing telephone connection entries on remote system merlin include the following.

Systems File

A Systems file on merlin should contain the following entry for venus , including a phone number and a dialing prefix:

venus Any ACU 1200 intown4362 "" in:--in: umerlin word: oaktree

System merlin can call system venus at any time, using an ACU device at 1200 baud and logging in as user umerlin with the password oaktree . The telephone number is expanded based on the code intown in the Dialcodes file, and the device to be used is determined based on the Type and Class entries. Accordingly, BNU checks the Devices file(s) for a device of type ACU and class 1200 .

Dialcodes File

The Dialcodes file on system merlin contains the following dial-code prefix for use with the number in the Systems file:

intown 9=325

Therefore, the expanded telephone number to reach system venus is 9=3254362 .

Devices File

A Devices file on system merlin should contain the following entry for the connection to venus :

ACU  tty1  -  1200  hayes \T

The ACU is attached to port tty1 , and the dialer is hayes . The telephone number is expanded with information from the Dialcodes file. BNU checks the Dialers files for an entry for a hayes modem.

Dialers File

A Dialers file used by uucico on system merlin should contain the following entry for its modem:

hayes  =,-,  ""  \dAT\r\c OK \pATDT\T\r\c CONNECT
Permissions File

The Permissions file on system merlin contains the following entries specifying system venus 's access to merlin :

LOGNAME=uvenus SENDFILES=call REQUEST=no \
WRITE=/var/spool/uucppublic:/home/venus \
READ=/var/spool/uucppublic:/home/venus 
MACHINE=merlin:venus VALIDATE=uvenus  \
READ=/ WRITE=/ COMMANDS=ALL REQUEST=yes \
NOREAD=/etc/uucp:/usr/etc/secure \
NOWRITE=/etc/uucp:/usr/etc/secure

BNU Configuration for a Direct Connection Example

The following files are set up for a hardwired connection between systems zeus and hera , where zeus is considered the local system and hera the remote system. The hardwired device on system zeus is tty5 ; on system hera it is tty1 . The speed of the connection is 1200 bps. The login ID for system zeus on system hera is uzeus , and the associated password is thunder . The login ID for system hera on system zeus is uhera , and the associated password is portent .

Entries in the Local System's Files

Files containing telephone connection entries on local system venus include the following.

Systems File

A Systems file on zeus should contain the following entry for the remote system hera :

hera Any hera 1200 - "" \r\d\r\d\r in:--in: uzeus word:  thunder

This entry specifies that system hera can log in to system zeus at any time, using a direct connection specified in the Devices files. To find the entry in the Devices files, BNU uses the third and fourth fields of the Systems entry. Thus BNU looks for an entry in the Devices files with a Type of hera and a Class of 1200 . System zeus logs in to system hera as user uzeus with the password thunder .

Devices File

A Devices file on zeus should contain the following entry in order to connect to the remote system hera :

hera    tty5  -  1200  direct

This entry specifies that system zeus uses the device tty5 at 1200 bps to communicate with system hera . Note that the Dialer in both Dialer-Token Pairs fields is direct . When connecting to system hera , BNU checks the Dialers file for a direct entry.

Dialers File

A Dialers file on system zeus must contain the following entry for direct connections:

direct

This specifies that no handshaking is required on the direct connection.

Permissions File

The Permissions file on the local system zeus contains the following entry specifying the ways in which the remote system hera can conduct uucico and uuxqt transactions with zeus :

LOGNAME=uhera MACHINE=hera VALIDATE=uhera REQUEST=yes \
SENDFILES=yes MACHINE=hera READ=/ WRITE=/ COMMANDS=ALL

This entry specifies that system hera logs in as uhera . Since the VALIDATE=uhera option is included, system hera cannot log in to system zeus with any other login ID, nor can any other remote system use the uhera ID. System hera can read and write to any directory on system zeus , and can send and request files regardless of who initiated the call. System hera can also initiate any commands on system zeus .

Note: Since the permissions that are granted are the same regardless of which system initiated the connection, the LOGNAME and MACHINE entries have been combined. Separately, they are: 
LOGNAME=uhera REQUEST=yes SENDFILES=yes READ=/ WRITE=/
MACHINE=zeus:hera VALIDATE=uhera READ=/ WRITE=/ REQUEST=yes \
COMMANDS=ALL
Attention: Providing the permissions in the preceding example is equivalent to giving any user on the remote system a login ID on the local system. Such liberal permissions can jeopardize your security and should usually be given only to well-trusted remote systems at the same site.

Entries in the Remote System's Files

Files containing telephone connection entries on remote system merlin include the following.

Systems File

A Systems file on system hera must contain the following entry for zeus :

zeus Any zeus 1200 - "" \r\d\r\d\r in:--in: uhera word: portent

This entry specifies that system hera can log in to system zeus at any time, using a direct connection specified in the Devices file(s). To find the entry in the Devices files, BNU uses the third and fourth fields of the Systems entry. Thus BNU looks for an entry in the Devices files with a Type of zeus and a Class of 1200 . System hera logs in to system zeus as user uhera with the password portent .

Devices File

A Devices file on system hera must contain the following entry for communications with zeus :

zeus    tty1  -  1200  direct

This entry specifies that system hera uses the device tty1 at 1200 bps to communicate with system zeus . Since the Dialer is specified as direct , BNU checks the Dialers files for a direct entry.

Dialers File

A Dialers file on system hera must contain the following entry for direct connections:

direct

This specifies that no dialer configuration is required on the direct connection.

Permissions File

The Permissions file on system hera contains the following entries specifying the ways zeus can conduct uucico and uuxqt transactions with hera :

LOGNAME=uzeus REQUEST=yes SENDFILES=yes READ=/ WRITE=/
MACHINE=hera:zeus VALIDATE=uzeus REQUEST=yes COMMANDS=ALL READ=/\
WRITE=/

These entries specify that system zeus logs in to system hera as uzeus . Because the VALIDATE=uzeus option is included, system zeus cannot log in to system hera with any other login ID, nor can any other remote system use the uzeus ID. System zeus can read and write to any directory on system hera , and can send and request files regardless of who initiated the call. System zeus can also initiate any commands on system hera .

Attention: Providing the permissions in the preceding example is equivalent to giving any user on the remote system a login ID on the local system. Such liberal permissions can jeopardize your security and normally should be given only to remote systems at the same site.
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