UUCP Reference
This chapter provides reference information for working with UUCP. The following topics are covered:
UUCP /etc/uucp/Systems File
The /etc/uucp/Systems file contains the information that is needed by the uucico daemon to establish a communication link to a remote computer. /etc/uucp/Systems is the first file you need to edit to configure UUCP.
Each entry in the Systems file represents a remote computer with which your host communicates. A particular host can have more than one entry. The additional entries represent alternative communication paths that are tried in sequential order. In addition, by default UUCP prevents any computer that does not appear in /etc/uucp/Systems from logging in to your host.
Using the Sysfiles file, you can define several files to be used as Systems files. See "UUCP /etc/uucp/Sysfiles File" for a description of Sysfiles.
Each entry in the Systems file has the following format:
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The following example shows the fields of the Systems file.
Example 40-1 Fields in /etc/uucp/Systems
System-Name Time Type Speed Phone Chat Script Arabian Any ACUEC 38400 111222 Login: Puucp ssword:beledi |
UUCP System-Name Field
This field contains the node name of the remote computer. On TCP/IP networks, this name can be the machine's host name or a name that is created specifically for UUCP communications through the /etc/uucp/Sysname file. See "UUCP /etc/uucp/Systems File". In Example 40-1, the System-Name field contains an entry for remote host arabian.
UUCP Time Field
This field specifies the day of week and time of day when the remote computer can be called. The format of the Time field follows:
daytime[;retry]
The day portion can be a list that contains some of the following entries.
Table 40-1 Day Field
For individual days. | |
For any weekday. | |
For any day. | |
Your host never initiates a call to the remote computer. The call must be initiated by the remote computer. Your host is then operating in passive mode. |
Example 40-1 shows Any in the Time field, which indicates that host arabian can be called at any time.
The time portion should be a range of times that are specified in 24-hour notation, for example, 0800-1230 for 8:30 a.m. to 12:30 p.m. If no time portion is specified, any time of day is assumed to be allowed for the call.
A time range that spans 0000 is permitted. For example, 0800-0600 means all times are allowed other than times between 6 a.m. and 8 a.m.
UUCP Retry Subfield
The Retry subfield enables you to specify the minimum time (in minutes) before a retry, following a failed attempt. The default wait is 60 minutes. The subfield separator is a semicolon (;). For example, Any;9 is interpreted as call any time, but wait at least 9 minutes before retrying after a failure occurs.
If you do not specify a retry entry, an exponential back-off algorithm is used. This means that UUCP starts with a default wait time that grows larger as the number of failed attempts increases. For example, suppose the initial retry time is 5 minutes. If no response occurs, the next retry is 10 minutes later. The next retry is 20 minutes later, and so on until the maximum retry time of 23 hours is reached. If retry is specified, that is always the retry time. Otherwise, the back-off algorithm is used.
UUCP Type Field
This field contains the device type that should be used to establish the communication link to the remote computer. The keyword that is used in this field is matched against the first field of Devices file entries.
Example 40-2 Type Field and /etc/uucp/Devices File
File Name System-Name Time Type Speed Phone Chat Script Systems arabian Any ACUEC, g 38400 1112222 ogin: Puucp ssword:beledi |
You can define the protocol that is used to contact the system by adding it on to the Type field. The previous example shows how to attach the protocol g to the device type ACUEC. For information on protocols, see "UUCP Protocol Definitions in the Devices File".
UUCP Speed Field
This field (also known as the Class field) specifies the transfer speed of the device that is used in establishing the communication link. The UUCP speed field can contain a letter and speed (for example, C1200, D1200) to differentiate between classes of dialers (refer to "UUCP Class Field").
Some devices can be used at any speed, so the keyword Any can be used. This field must match the Class field in the associated Devices file entry.
Example 40-3 Speed Field and /etc/uucp/Devices File
File Name System-Name Time Type Speed Phone Chat Script Systems eagle Any ACU, g D1200 NY3251 ogin: nuucp ssword: Oakgrass |
If information is not required for this field, use a dash (-) as a placeholder for the field.
UUCP Phone Field
This field enables you to specify the telephone number (token) of the remote computer for automatic dialers (port selectors). The telephone number consists of an optional alphabetic abbreviation and a numeric part. If an abbreviation is used, it must be one that is listed in the Dialcodes file.
Example 40-4 Phone Field Correspondence
File Name System-Name Time Type Speed Phone Chat Script Systems nubian Any ACU 2400 NY5551212 ogin: Puucp ssword:Passuan |
In the System-Name string, an equals sign (=) tells the ACU to wait for a secondary dial tone before dialing the remaining digits. A dash (-) in the string instructs the ACU to pause four seconds before dialing the next digit.
If your computer is connected to a port selector, you can access other computers that are connected to that selector. The Systems file entries for these remote machines should not have a telephone number in the Phone field. Instead, this field should contain the token to be passed on to the switch. In this way, the port selector knows the remote machine with which your host wants to communicate, usually just the system name. The associated Devices file entry should have a \D at the end of the entry to ensure that this field is not translated by using the Dialcodes file.
UUCP Chat Script Field
This field (also called the Login field) contains a string of characters that is called a chat-script. The chat-script contains the characters the local and remote machines must pass to each other in their initial conversation. Chat-scripts have the following format:
expect send [expect send] ....
expect represents the string that the local host expects to receive from the remote host to initiate conversation. send is the string the local host sends after it receives the expect string from the remote host. A chat-script can have more than one expect-send sequence.
A basic chat-script might contain the following:
Login prompt that the local host expects to receive from the remote machine
Login name that the local host sends to the remote machine in order to log in
Password prompt that the local host expects to receive from the remote machine
Password that the local host sends to the remote machine