Remote access in Bitnet


Henry Nussbacher (HANK%BARILVM.BITNET@wiscvm.wisc.edu)
Wed, 01 Apr 87 10:31:41 O


(Caveat - This description is primarily for people who have no idea how
 Bitnet works.)

Greg,

The concept of remote access doesn't exist in Bitnet. The protocols in
Bitnet are as follows:

1) One-way File Transfer - any user is allowed to send a file to any other
   user. Since the file ends up in the destination users spool system
   (or some emulation thereof) there is no problem with access control.

2) Interactive Message - any user can send a one line message (max 160
   characters) to any other user. All you need to know is the destination
   user and node. If the user is not logged on or a link is down you are
   told so.

Based on these two primitives - Bitnet has built various other
pseudo-protocols. From #1 above - we are able to do mail, list explosion,
computer conferencing, general file transfer. From #2 above, Bitnet has
developed a CB (Chat) system.

By combined both of the basic primitives above, a file server can be set
up at any node that will trap incoming 'Interactive Messages' - which
contain a command and process the command and send the results back to the
user via the 'One-Way File Transfer' mechanism. This method allows users
to sit at their machine and issue commands like DIR or LIST to some remote
file server and then issue some SEND commands to retrieve the files they
want. There is no need in that case to do any sort of remote connect
(anonymous FTP).

Most servers (200+) in Bitnet also accept transactions via files or RFC822
mail. Lately, various servers in Arpanet have decided that is also a 'clever'
thing to have, so we have things like archive-request@simtel20.arpa and
service@sri-nic.arpa popping up (I expect more before the end of th year).

So to answer your question:

> a remote file they own

They cannot access it. Yup would be nice and that is just one reason why
Bitnet should convert to Tcp/Ip. Incidentally, there is a program I
distribute in Bitnet that allows this remote access to a file the person
owns but it is a private convention. The program runs as a task (and
therefore must be running when the remote user wants access to his/her files).
and the user needs to set up a remote access password. It uses the
Interactive Message Primitive to send and receive data, and each command
you want executed on the remote host must be prefixed with your remote pswd.
Not as elegent as TELNET but when the entire concept of TELNET doesn't exist
it is the best one can do.

> a remote file they don't own, but is not protected

Only if the file is available via a remote file server can they access it.

> a remote file they don't own, but is protected

They can't access it.

Hope this helps.

Hank



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