TCP/IP Configuration and Management Manual

NonStop TCP/IP Processes and Protocols
TCP/IP Configuration and Management Manual—427132-004
B-27
Simple Mail Transfer Protocol (SMTP)
system. Because these programs are not connection-oriented, and they do not use any
user-authentication mechanism, you must place some restrictions on the files that can
be sent and received from a remote system.
The TFTP server imposes certain restrictions when you retrieve a file from a NonStop
system. You cannot retrieve a file unless it is readable to the network (unless its access
security is NXXX). The write/execute/purge permissions may be anything.
The TFTP server also imposes certain restrictions when you try to store a file on a
NonStop system. The file must already exist on the NonStop system, and it must be
network writable (its access security is XNXX).
The system manager can place further restrictions on the machine in which the TFTP
server is running by specifying public volume.subvolume names on the command line
when starting the TFTP server. If the names are specified, files can be retrieved from
and stored on the specified volume.subvolume. Up to six separate subvolumes can be
specified.
New files may be created in the specified subvolumes. However, if a file already exists,
it must be secured XNXX if it is to be written to. New files are created by the TFTP
server with the permissions NNNG. These permissions allow remote users to overwrite
the new files.
The TFTP client provides the user interface to the Internet TFTP. A TFTP client may
store files virtually anywhere, depending only on the client’s login restrictions.
For a detailed description of the operation of the TFTP server and client, refer to the
TCP/IP Applications and Utilities User Guide. For more detailed technical information
on the TFTP, refer to IEN 133 (
DDN Protocol Handbook, Volume 2, DDN Network
Information Center, December, 1985, pp. 2-965 through 2-984). Also, refer to the book
Internetworking with TCP/IP (Douglas E. Comer, Prentice Hall, 1991).
Simple Mail Transfer Protocol (SMTP)
The Simple Mail Transfer Protocol (SMTP) is a protocol implemented on a NonStop
system that provides an interface between TRANSFER Mail systems and SMTP hosts.
The SMTP protocol enables TRANSFER Mail users (referred to as TRANSFER hosts)
to send and receive messages to users on SMTP hosts.
The SMTP protocol also relays SMTP messages between SMTP hosts by acting as an
intermediate node that stores and forwards SMTP messages.
TRANSFER
The SMTP gateway does not deliver mail directly to your terminal; it uses TRANSFER
as the vehicle for local delivery and also for storing mail that has to be forwarded.
TRANSFER is a high-level software product that reliably supports communication
between users, devices, and processes. TRANSFER maintains a database that
describes users and provides holding areas for packages.