4.2 Transfer by Mail

On some systems, direct remote spooled execution is not possible. However, most systems support electronic mail, and a news article can be sent as mail. One approach is to send a mail message which is identical to the news message: the mail headers are the news headers, and the mail body is the news body. By convention, this mail is sent to the user "newsmail" on the remote machine.

One problem with this method is that it may not be possible to convince the mail system that the From line of the message is valid, since the mail message was generated by a program on a system different from the source of the news article. Another problem is that error messages caused by the mail transmission would be sent to the originator of the news article, who has no control over news transmission between two cooperating hosts and does not know who to contact. Transmission error messages should be directed to a responsible contact person on the sending machine.

A solution to this problem is to encapsulate the news article into a mail message, such that the entire article (headers and body) are part of the body of the mail message. The convention here is that such mail is sent to user "rnews" on the remote system. A mail message body is generated by prepending the letter "N" to each line of the news article, and then attaching whatever mail headers are convenient to generate. The N's are attached to prevent any special lines in the news article from interfering with mail transmission, and to prevent any extra lines inserted by the mailer (headers, blank lines, etc.) from becoming part of the news article. A program on the receiving machine receives mail to "rnews", extracting the article itself and invoking the "rnews" program. An example in this format might look like this:

     Date: Monday, 3-Jan-83 08:33:47 MST
     From: news@cbosgd.UUCP
     Subject: network news article
     To: rnews@npois.UUCP

     NRelay-Version: B 2.10  2/13/83 cbosgd.UUCP
     NPosting-Version: B 2.9 6/21/82 sask.UUCP
     NPath: cbosgd!mhuxj!harpo!utah-cs!sask!derek
     NFrom: derek@sask.UUCP (Derek Andrew)
     NNewsgroups: net.test
     NSubject: necessary test
     NMessage-ID: <176@sask.UUCP>
     NDate: Monday, 3-Jan-83 00:59:15 MST
     N
     NThis really is a test.  If anyone out there more than 6
     Nhops away would kindly confirm this note I would
     Nappreciate it.  We suspect that our news postings
     Nare not getting out into the world.
     N

Using mail solves the spooling problem, since mail must always be spooled if the destination host is down. However, it adds more overhead to the transmission process (to encapsulate and extract the article) and makes it harder for software to give different priorities to news and mail.