UUCP /etc/uucp/Sysfiles File
The /etc/uucp/Sysfiles file lets you assign different files to be used by uucp and cu as Systems, Devices, and Dialers files. For more information on cu, see the cu(1C) man page. You can use Sysfiles for the following:
Different Systems files so that requests for login services can be made to different addresses than uucp services.
Different Dialers files so that you can assign different handshaking for cu and uucp.
Multiple Systems, Dialers, and Devices files. The Systems file in particular can become large, making it more convenient to split it into several smaller files.
The format of the Sysfiles file is as follows:
service=w systems=x:x dialers=y:y devices=z:z |
w represents uucico, cu, or both commands separated by a colon. x represents one or more files to be used as the Systems file, with each file name separated by a colon and read in the order that is presented. y represents one or more files to be used as the Dialers file. z is one or more files to be used as the Devices file.
Each file name is assumed to be relative to the /etc/uucp directory, unless a full path is given.
The following sample, /etc/uucp/Sysfiles, defines a local Systems file (Local_Systems) in addition to the standard /etc/uucp/Systems file:
service=uucico:cu systems=Systems :Local_Systems |
When this entry is in /etc/uucp/Sysfiles, both uucico and cu first check in the standard /etc/uucp/Systems. If the system they are trying to call doesn't have an entry in that file, or if the entries in the file fail, then both commands check /etc/uucp/Local_Systems.
As specified in the previous entry, cu and uucico share the Dialers and Devices files.
When different Systems files are defined for uucico and cu services, your machine stores two different lists of Systems. You can print the uucico list by using the uuname command or the cu list by using the uuname -C command. The following is another example of the file, which shows that the alternate files are consulted first and the default files are consulted if necessary:
service=uucico systems=Systems.cico:Systems dialers=Dialers.cico:Dialers \ devices=Devices.cico:Devices service=cu systems=Systems.cu:Systems \ dialers=Dialers.cu:Dialers \ devices=Devices.cu:Devices |
UUCP /etc/uucp/Sysname File
Every machine that uses UUCP must have an identifying name, often referred to as the node name. This is the name that appears in the remote machine's /etc/uucp/Systems file, along with the chat-script and other identifying information. Normally, UUCP uses the same node name as is returned by the uname -n command, which is also used by TCP/IP.
You can specify a UUCP node name independent of the TCP/IP host name by creating the /etc/uucp/Sysname file. The file has a one-line entry that contains the UUCP node name for your system.
UUCP /etc/uucp/Permissions File
The /etc/uucp/Permissions file specifies the permissions that remote computers have for login, file access, and command execution. Some options restrict the remote computer's ability to request files and its ability to receive files that are queued by the local machine. Another option is available that specifies the commands that a remote machine can execute on the local computer.
UUCP Structuring Entries
Each entry is a logical line, with physical lines terminated by a backslash (\) to indicate continuation. Entries are composed of options that are delimited by blank space. Each option is a name-value pair in the following format:
name=value
Values can be colon-separated lists. No blank space is allowed within an option assignment.
Comment lines begin with a pound sign (#), and they occupy the entire line up to a newline character. Blank lines are ignored (even within multiple-line entries).
The types of Permissions file entries are as follows:
LOGNAME - Specifies the permissions that become effective when a remote computer logs in to (calls) your computer.
Note - When a remote machine calls you, its identity is questionable unless it has a unique login and verifiable password.
MACHINE - Specifies permissions that become effective when your computer logs in to (calls) a remote computer.
LOGNAME entries contain a LOGNAME option and MACHINE entries contain a MACHINE option. One entry can contain both options.
UUCP Considerations
When using the Permissions file to restrict the level of access that is granted to remote computers, you should consider the following:
All login IDs that are used by remote computers to log in for UUCP communications must appear in one and only one LOGNAME entry.
Any site that is called with a name that does not appear in a MACHINE entry, has the following default permissions or restrictions:
UUCP REQUEST Option
When a remote computer calls your computer and requests to receive a file, this request can be granted or denied. The REQUEST option specifies whether the remote computer can request to set up file transfers from your computer. The string REQUEST=yes specifies that the remote computer can request to transfer files from your computer. The string REQUEST=no specifies that the remote computer cannot request to receive files from your computer. REQUEST=no, the default value, is used if the REQUEST option is not specified. The REQUEST option can appear in either a LOGNAME entry (the remote computer calls you) or a MACHINE entry (you call remote computer).
UUCP SENDFILES Option
When a remote computer calls your computer and completes its work, it can attempt to retrieve work your computer has queued for it. The SENDFILES option specifies whether your computer can send the work that is queued for the remote computer.
The string SENDFILES=yes specifies that your computer can send the work that is queued for the remote computer if it is logged in as one of the names in the LOGNAME option. This string is mandatory if you have entered Never in the Time field of /etc/uucp/Systems. This designation sets up your local machine in passive mode, but it is not allowed to initiate a call to this particular remote computer. See "UUCP /etc/uucp/Systems File" for more information.
The string SENDFILES=call specifies that files that are queued in your computer are sent only when your computer calls the remote computer. The call value is the default for the SENDFILES option. This option is only significant in LOGNAME entries because MACHINE entries apply when calls are sent to remote computers. If the option is used with a MACHINE entry, it is ignored.
UUCP MYNAME Option
This option enables you to designate a unique UUCP node name for your computer in addition to its TCP/IP host name, as returned by the hostname command. For instance, if you have unknowingly given your host the same name as that of some other system, you can set the MYNAME option of the Permissions file. Suppose that you want your organization to be known as widget. If all your modems are connected to a machine with the host name gadget, you can have an entry in gadget's Permissions file that reads as follows:
service=uucico systems=Systems.cico:Systems dialers=Dialers.cico:Dialers \ devices=Devices.cico:Devices service=cu systems=Systems.cu:Systems \ dialers=Dialers.cu:Dialers \ devices=Devices.cu:Devices |
Now the system world can log in to the machine gadget as if it were logging in to widget. In order for machine world to know you also by the aliased name widget when you call it, you can have an entry that reads as follows:
MACHINE=world MYNAME=widget |
You can also use the MYNAME option for testing purposes, as it allows your machine to call itself. However, because this option could be used to mask the real identity of a machine, you should use the VALIDATE option, as described in "UUCP VALIDATE Option".