Configuring UUCP over TCP/IP
There are several reasons you may wish to configure
UUCP over TCP/IP. Some sites do not provide
ftpd or rshd servers and/or their
respective clients, ftp and rcp.
Thus transferring files across a
TCP/IP network is not an option with these systems.
Additionally, some versions of TCP/IP do not provide the
Simple Mail Transfer Protocol, SMTP, for mail transfer.
In these cases, setting up UUCP to use TCP/IP may be an
option to allow both file transfer and exchange of mail
between such systems.
In the following paragraphs, the word ``client'' refers to a system that executes the uucp or uux command, while the term ``server'' or ``listener'' refers to a system that responds to a request from a client system.
There are two approaches to configuring UUCP over TCP/IP: the TCP socket interface and TLI/XTI (Transport Layer Interface and X/Open Transport Interface).
The server system uses the inetd superserver to listen for incoming uucp requests on TCP port 540. When receiving a request from a client uucico process, the server system forks the uucpd daemon, which logs in the client with the shell uucico. The two uucico processes can then transfer information similar to the way they would in a standard serial line configuration.
The server system uses a process called listen to wait for requests from a predefined TCP port and then when receiving a request, forks a uucico process directly, bypassing the standard UUCP login sequence.