
Section 11 Electronic Mail
	by Mic Kaczmarczik, The University of Texas Computation Center

Computer users have been sending private messages to  each  other
almost  as long as it has been possible for more than one user to
use the system at once.  As  computer  networks  have  developed,
this  capability  has  become one of the most widely used network
services. This chapter is a brief primer on electronic mail; what
it  is,  how  to  analyze  mail  addresses, and addressing syntax
tables for sending mail between the computer  networks  described
in this directory.

The term electronic mail (E-mail),  in  general,  refers  to  any
method whereby computer users exchange private messages with oth-
er computer users.  E-mail is a distinct service from  electronic
bulletin  boards,  network news, and on-line databases; E-mail is
devoted to private, person-to-person communication.   On  a  very
basic  level,  there are several things you need in order to send
electronic mail: 

	1. Access to a computer which provides E-mail  ser-
	vices.  Access to a system listed in this directory may allow you
	to exchange E-mail messages with users  on  many  other  computer
	systems  around  the world.  However, due to differences in poli-
	cies, software, hardware, and funding, not all of  these  systems
	may provide the same level of access to all networks.  You should
	contact the appropriate people at your  site  for  details.   

	2. You must  know  how  to  use  your  system's E-mail facilities.  
	This directory cannot provide all the answers, so you must avail your-
	self  of the help and consulting services available for your system
	The help system on your computer is the primary  source  for
	documentation  on  how  to get mail started on its way.  

	3. You must know the E-mail address of the individual(s) you with to 
	communicate with. This means the intended recipient must have an 
	account on a computer system as well.  You must also have some idea of
	how  to navigate from the network(s) your system is on to the re-
	mote system.  

	The syntax for addressing E-mail to local users is almost always simple.
	Addressing  for  users on other systems varies in difficulty, while 
	cross-network mail can be  very  complex. The tables in this chapter 
	provide the fundamentals of getting from one network to another.  

To obtain address  information it is possible on some networks to directly 
request user information from a remote network site.  However, the simplest  and
most  efficient  technique  is  to simply give the person a phone
call (or write them a letter), asking for 

	1. The name and type of computer that person has an account on 

	2. The user name associated with that person 

	3. The name(s) of any computer network(s) the computer participates in.  
	This last step is vital, since unless the networks you and the other 
	person are on are connected in some way, you cannot exchange electronic
	mail. 

Once you have correct E-mail addresses for each other, you can then exchange
messages. The following section discusses the terminology you will need to
be familiar with in order to correctly determine another's  electronic mail 
address.


                 Network and E-Mail Terminology

Networks

	The term network  can mean  many things, depending on the
context  it  is used in. A physical  network  may be defined as a 
group of computer systems which 1) are directly connected to each
other  via a wire, cable, or other low-level communications chan-
nel, and 2) can communicate over  this  channel  using  a  common
language or protocol. The set of logical networks is much
larger.  A logical network is merely  a  group  of  systems  that
somehow  have  a way of exchanging data with each other.  Logical
networks typically have slower response times than physical  net-
works,  and  many  do  not  provide  the full range of networking
resources, such as remote terminal access, file sharing and other
functions  requiring  high  speed connections. Electronic mail is
the most common service provided by logical networks.

Gateways

	Since  there is more than one kind of  network,  computer
systems on one network must use an intermediary agent to transfer
data and messages to  another network. The  generic  term gateway
refers to such agents, which provide services for exchanging data
between networks.  Gateways are used to increase  the  number  of
systems  reachable  by  a particular system.  Many large networks
across the world are interconnected via E-mail gateways.  For ex-
ample, the Internet-to-CSNET mail relay (known as RELAY.CS.NET on
both sides of the gateway) is a mail gateway system; it can route
mail  and  data  between  systems on the ARPA Internet and CSNET.
Another example is the Internet-to-BITNET  mail  gateway  at  the
City  University  of  New  York,  known as INTERBIT on the BITNET
side, and CUNYVM.CUNY.EDU on the Internet side.

Internets
	An Internet (with a lower case i) is a term for  a  logi-
cal network whose systems use the same high-level networking pro-
tocol but different physical network hardware (e.g.  TCP/IP  net-
works  using  both Ethernet and low-speed serial lines). Data in-
tended for a system in another part of the internet is passed  to
a gateway system, which forwards the data to its destination.  To
the user, the entire internet appears to be  part  of  the  local
physical  network,  and all services normally associated with the
local network are available on the all  parts  of  the  internet.
Thus  service on an internet is typically faster than other sorts
of networks, because the intent is to make the internet look like
one  big  physical network.  The term Internet (with a capital I)
is used to refer to a specific case of  an  internet.   The  most
widely known internet is the ARPA Internet, a nationwide internet
that uses TCP/IP as its  high-level  networking  protocol.   When
someone  mentions  the Internet, chances are it's in reference to
the ARPA Internet.  Another internet (lowercase i) is THENET, the
Texas  Higher Education Network, which is uses DECnet as its pri-
mary high-level protocol.




Store and Forward Networks Some networks  do  not  provide  tran-
sparent  connections  between  hosts in the network; in such net-
works, data is transferred from host to host  in  a  step-by-step
fashion,  on their way to the final destination.  Such store-and-
forward networks are often used for transferring mail  and  files
over  phone  lines and other low-speed, intermittent connections.
UUCP and BITNET are major examples of store and forward networks.
UUCP  differs from BITNET in that UUCP often requires the user to
route the message explicitly from the source to  the  destination
(.e.g site1!site2!user), while BITNET allows a sender to imply to
specify the destination (e.g.  user@bitnet-host).   Depending  on
the  software installed, some mail systems may allow UUCP mail to
be  addressed  directly  to  the  destination  (e.g.   user@uucp-
host.UUCP);  contact  your local system management to find out if
this is possible.



                    Addressing Syntax Primer

Each network protocol has a particular style for addressing  mail
to  a  user on another system on the same network.  This standard
(or canonical) address syntax ignores the issues of gateways, ad-
ministrative concerns, and nonstandard mail interfaces.  Below is
table of common standard address formats, their underlying  high-
level networking protocols, and some actual logical networks that
use these formats.  You can use these tables  to  analyze  return
addresses  in the messages you receive and determine how the mail
actually got to you.  Every mail gateway accepts a slightly  dif-
ferent  set  of addressing syntaxes, so there are many variations
on the styles presented above.  Using the guides below,  contact-
ing  your system administrator for assistance and trial and error
are the usual methods of determining a reliable and expedient  E-
mail  path.

	Syntax  			Protocol        Network                 
	-------------------------------------------------------------------
	
	user@host.subdomain.domain	TCP/IP		ARPA Internet, CSNET
	user@host			RSCS/NJE	BITNET
	host::user			DECnet		THEnet, SPAN
	host!user			UUCP		UUCP mail network


Here are some of the formats used to gateway mail between common networks: 

	Syntax				Usage
	-------------------------------------------------------------------

	user%host.BITNET@gateway	ARPA Internet to BITNET
	user%host.DECNET@gateway	ARPA Internet to DECnet
	@gateway:user@host		New style Internet gateway
	user%host%gateway2@gateway	Multiple gateways
	host!user@gateway		Internet to UUCP
	host1!...!hsotn!user		UUCP routing
	host1::host2::user		DECnet routing



                     Mail Addressing Tables

This section contains crib sheets for addressing  mail  from  one
network  to  another.   For each major network in this directory,
there is a table describing the most well known (or reliable) way
to  exchange  mail  with  users on the other networks.  Note that
there may be a better way to get  from  your  system  to  another
specific system, depending on administrative details that must be
determined locally.  The following tables use the convention that
boldface  characters and punctuation are literal parts of the ad-
dress, to be used as-is.  The string network-host (e.g.   THEnet-
host),  means  the full host name according to the conventions of
the particular network.  In the case of  the  ARPA  Internet  and
CSNET,  this  means  the  complete  ARPA Internet hostname, (e.g.
NIC.SRI.COM or  ZOTZ.CS.UTEXAS.EDU).   In  the  case  of  BITNET,
THENET, and SPAN, this usually means a much simpler name like IN-
TERBIT or UTSPAN, to which a network name or  type  is  sometimes
appended (e.g.  UTSPAN.DECNET).  These address formats completely
ignore the question of exactly how to specify an  E-mail  address
to  the  mail  system  running on your computer; it is beyond the
scope of this document to provide a  complete  cookbook  for  ad-
dressing  mail.   








ARPA Internet
--------------

This table specifies addressing formats for ARPA Internet hosts.

	   Addressing Formats For Sending From ARPA Internet

	Network			Sending From ARPA Internet
	-----------------------------------------------------------------
	ARPA Internet	user@Internet-host
	BITNET		user%BITNET-host.BITNET@CUNYVM.CUNY.EDU
	CSNET		user%CSNET-host@relay.cs.net
	SPAN		SPAN-host::user%UTSPAN.DECNET@UTADNX.CC.UTEXAS.EDU
	THEnet		user%THEnet-host.DECNET@UTADNX.CC.UTEXAS.EDU


	   Addressing Formats For Sending to ARPA Internet

	Network			Sending to ARPA Internet
	-----------------------------------------------------------------
	ARPA Internet	user@Internet-host
	BITNET		See below for BITNET to ARPA Internet gateways
	CSNET		user%Internet-host@relay.cs.net
	SPAN		UTSPAN::UTADNX::MAILER%"user@Internet-host"
	THEnet		UTADNX::MAILER%"user@Internet-host"

BITNET  
-----
This   table specifies  addressing  formats  for BITNET sites.
Due to characteristics of the underlying communications software,
BITNET is perhaps the most difficult network to send mail to and
from. Some mail systems on BITNET hosts have been modified to make
addressing to other networks much easier; contact your local system
management or consulting services to see if this has been done on
your system.

	   Addressing Formats for Sending From BITNET

	Network			Sending From BITNET
	-----------------------------------------------------------------
	ARPA Internet	See below for BITNET to ARPA Internet gateways
	BITNET		user@BITNET-host
	CSNET		See below for BITNET to CSNET gateways
	SPAN		See below for BITNET to SPAN gateways
	THEnet		See below for BITNET to THEnet gateways

	   Addressing Formats for Sending to BITNET

	Network			Sending To BITNET
	-----------------------------------------------------------------
	ARPA Internet	user%BITNET-host.BITNET@CUNYVM.CUNY.EDU
	BITNET		user@BITNET-host
	CSNET 		user%BITNET-host.BITNET@CUNYVM.CUNY.EDU
	SPAN		UTSPAN::UTADNX::BITNET%"user@BITNET-host"
	THEnet		UTADNX::BITNET%"user@BITNET-host"


CSNET 
----

This table describes addressing formats  for  CSNET  hosts.
CSNET  has  the  same  host name syntax as the ARPA Internet, but
mail is gatewayed to the ARPA Internet via the host RELAY.CS.NET.
On  some systems, it may be possible to avoid explicitly mention-
ing the gateway RELAY.CS.NET when routing mail through  the  ARPA
Internet;  contact your local system administration or consulting
services to see if this is possible.

	   Addressing Formats for Sending From CSNET

	Network			Sending From CSNET
	-----------------------------------------------------------------
	ARPA Internet	user%Internet-host@RELAY.CS.NET
	BITNET		user%BITNET-host.BITNET%CUNYVM.CUNY.EDU@RELAY.CS.NET
	CSNET		user%CSNET-host
	SPAN		span-host::user%UTPSAN.DECNET%UTADNX.CC.UTEXAS.EDU@ -
								RELAY.CS.NET
	THEnet		user%THENET-host.DECNET%UTADNX.CC.UTEXAS.EDU@ -
	
	   Addressing Formats for Sending To CSNET

	Network			Sending To CSNET
	-----------------------------------------------------------------
	ARPA Internet	user%CSNET-host@RELAY.CS.NET
	BITNET		See below for BITNET to CSNET gateways
	CSNET		user%CSNET-host
	SPAN		UTSPAN::UTADNX::MAILER%"user%CSNET-host@RELAY.CS.NET"
	THEnet		UTADNX::MAILER%"user%CSNET-host@RELAY.CS.NET"

SPAN
----

This table describes  addressing  formats  for  SPAN  hosts.
SPAN  is  the most distant network in this directory, in terms of
the number of gateways necessary to exchange mail with other net-
works.

	   Addressing Formats for Sending From SPAN

	Network			Sending From SPAN
	-----------------------------------------------------------------
	ARPA Internet	UTSPAN::UTADNX::MAILER%"user@Internet-host"
	BITNET		UTSPAN::UTADNX::BITNET%"user@BITNET-host"
	CSNET		UTSPAN::UTADNX::MAILER%"user%CSNET-host@RELAY.CS.NET"
	SPAN		SPAN-host::user
	THEnet		UTSPAN::THENET-host::user

	   Addressing Formats for Sending To SPAN

	Network			Sending To SPAN
	-----------------------------------------------------------------
	ARPA Internet	SPAN-host::user%UTSPAN.DECNET@UTADNX.CC.UTEXAS.EDU
	BITNET		See below for BITNET to SPAN gateways
	CSNET		SPAN-host::user%UTSPAN.DECNET%UTADNX.CC.UTEXAS.EDU@ -
								RELAY.CS.NET
	SPAN		SPAN-host::user
	THEnet		UTSPAN::SPAN-host::user


THEnet 
-----

This table describes addressing formats for THENET  hosts.
Some THENET hosts may have software installed that allows them to
participate in the ARPA Internet or BITNET,  in  which  case  the
more  direct  formats described under the appropriate network can
be used. Contact local system administrators or  consulting  ser-
vices to see if this is possible.

	   Addressing Formats for Sending From THEnet

	Network			Sending From THEnet
	-----------------------------------------------------------------
	ARPA Internet	UTADNX::MAILER%"user@Internet-host"
	BITNET		UTADNX::BITNET%"user@BITNET-host"
	CSNET		UTADNX::MAILER%"user%CSNET-host@RELAY.CS.NET"
	SPAN		UTSPAN::SPAN-host::user
	THEnet		THEnet-host::user

	   Addressing Formats for Sending To THEnet

	Network			Sending To THEnet
	-----------------------------------------------------------------
	ARPA Internet	user%THEnet-host.DECNET@UTADNX.CC.UTEXAS.EDU
	BITNET		see below for BITNET to THEnet gateways
	CSNET		user%THEnet-host.DECNET%UTADNX.CC.UTEXAS.EDU@ -
								RELAY.CS.NET
	SPAN		UTSPAN::THEnet-host::user
	THEnet		THEnet-host::user


                      BITNET Mail Gateways

Sending mail on BITNET sometimes necessitates the creation  of  a
specially  formatted  mail  file  that is forwarded to a specific
user ID on another BITNET host.  Mail  software  on  that  BITNET
host  then sends the mail over the desired network.  Many systems
on BITNET have had software installed that allows  you  to  avoid
this cumbersome technique, and simply send your mail to a regular
network address.  If this is not the case on your  system,  below
are file templates for gateways from BITNET to the other networks
in this directory.  

Sending the file 

In order to send these files from an IBM CMS system, use the commands

        CP SPOOL PUN RSCS
	CP TAG DEV PUN gateway deliveryagent
	PUNCH filename filetype filemode

	Where gateway and deliveryagent stand for the appropriate gateway
and delivery agent given below, and filename filetype filemode stand for the
specially formatted mail file.

	VMS users on systems using the JNET software package can send the 
files using the command:

	SEND/FILE filename deliveryagent@gateway

using the same definition of filename, deliveryagent, and gateway as before.




BITNET to ARPA Internet

	To send mail from BITNET to the ARPA Internet, create a specially
formatted mail message from the template below, then send the file to the
mail delivery agent SMTP on BITNET host INTERBIT.

	*****************************************************************
	HELO your-host.BITNET
	VERB ON
	TICK nnnn
	MAIL FROM:<your-username@your-host.BITNET>
	RCPT TO:<Internet-user@Internet-host>
	DATA
	Date: current date, e.g. 01 Jan 88 00:01 CDT
	From: your-username@your-host.BITNET
	To: Internet-user@Internet-host
	Subject: optional subject line
	Mandatory blank line between header and message!

	Message text. Complete message with a single period (.) by itself
	on a line. The TICK line specifies a ticket number that can be
	used to track down problems with sending the messge
	.
	QUIT
	*****************************************************************



BITNET to CSNET

	To send mail from BITNET to CSNET, create a specially formatted
mail message from the template below, then send the file to the mail delivery
agent SMTP on BITNET host INTERBIT.
	
	*****************************************************************
	HELO your-host.BITNET
	VERB ON
	TICK nnnn
	MAIL FROM:<your-username@your-host.BITNET>
	RCPT TO:<CSNET-user%CSNET-host@RELAY.CS.NET>
	DATA
	Date: current date, e.g. 01 Jan 88 00:01 CDT
	From: your-username@your-host.BITNET
	To: CSNET-user%CSNET-host@RELAY.CS.NET
	Subject: optional subject line
	Mandatory blank line between header and message!

	Message text. Complete message with a single period (.) by itself
	on a line. The TICK line specifies a ticket number that can be
	used to track down problems with sending the messge
	.
	QUIT
	*****************************************************************




BITNET to SPAN

	To send mail from BITNET to SPAN, create a specially formatted
mail message from the template below, then send the file to the mail
delivery agent SMTP on BITNET hsot INTERBIT.

	*****************************************************************
	HELO your-host.BITNET
	VERB ON
	TICK nnnn
	MAIL FROM:<your-username@your-host.BITNET>
	RCPT TO:<SPAN-host::SPAN-user%UTSPAN.DECNET@UTADNX.CC.UTEXAS.EDU>
	DATA
	Date: current date, in format dd mmm yy hh:mm CDT
	From: your-username@your-host.BITNET
	To: THENET-user%THENET-host.DECNET@UTADNX.CC.UTEXAS.EDU
	Subject: optional subject line
	Mandatory blank line between header and message!

	Message text. Complete message with a single period (.) by itself
	on a line. The TICK line specifies a ticket number that can be
	used to track down problems with sending the messge
	.
	QUIT
	*****************************************************************


BITNET to THEnet

	To send mail from BITNET to THEnet, create a specially formatted
mail message from the template below, then send the file to the mail delivery
agent SMTP on BITNET host INTERBIT.

	*****************************************************************
	HELO your-host.BITNET
	VERB ON
	TICK nnnn
	MAIL FROM:<your-username@your-host.BITNET>
	RCPT TO: <THENET-user%THENET-host.DECNET@UTADNX.CC.UTEXAS.EDU>
	DATA
	Date: current date, in format dd mmm yy hh:mm CDT
	From: your-username@your-host.BITNET
	To: THENET-user%THENET-host.DECNET@UTADNX.CC.UTEXAS.EDU
	Subject: optional subject line
	Mandatory blank line between header and message!

	Message text. Complete message with a single period (.) by itself
	on a line. The TICK line specifies a ticket number that can be
	used to track down problems with sending the messge
	.
	QUIT
	*****************************************************************
 