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... network News messages among USENET hosts. It describes the format
for messages themselves and gives partial standards for transmission
of news. The news transmission is not entirely in order to give a
...
... for messages themselves and gives partial standards for transmission
of news. The news transmission is not entirely in order to give a
good deal of flexibility to the hosts to choose transmission
hardware and software, to batch news, and so on.
...
... header is present, in which case the "From" header might
not be verified. Note that in all host and domain names, upper and
lower case are considered the same, thus "mark@cbosgd.ATT.COM",
...
... newsgroups from the list. Instead, the invalid newsgroups
should be ignored. For example, suppose host A subscribes to the
classes ...
... subscribes to the
classes btl.all and comp.all, and exchanges news messages with host
B, which subscribes to comp.all but not btl.all. Suppose A receives
...
...
where full_domain_name is the full name of the host at which the
message entered the network, including a domain ...
... message entered the network, including a domain that host is in, and
unique is any string of printing ASCII characters, not including "<"
...
... example, a valid Message-ID for a message submitted from host ucbvax
in domain "Berkeley.EDU" would be "<4123@ucbvax.Berkeley.EDU>".
...
... Programmers are urged not to make assumptions about the content of
Message-ID fields from other hosts, but to treat them as unknown
character strings. It is not safe, for example, to assume that a
Message-ID ...
... names should be added from the left. For example, the most recently
added name in the fourth example was teklabs. Letters, digits,
periods and hyphens are considered part of host names; other
punctuation, including blanks, are considered separators.
...
... address. It is intended to show the route the message
traveled to reach the local host. There are several uses for this
information. One is to monitor USENET routing ...
... routing for performance
reasons. Another is to establish a path to reach new hosts.
Perhaps the most important use is to cut down on redundant USENET
...
... USENET
traffic by failing to forward a message to a host that is known to
have already received it. In particular, when host A sends a
...
... traffic by failing to forward a message to a host that is known to
have already received it. In particular, when host A sends a
message to host B, the "Path" line includes A, so that host ...
... have already received it. In particular, when host A sends a
message to host B, the "Path" line includes A, so that host B will
not immediately send the message back to host ...
... host A sends a
message to host B, the "Path" line includes A, so that host B will
not immediately send the message back to host A. The name each host ...
... host B, the "Path" line includes A, so that host B will
not immediately send the message back to host A. The name each host
uses to identify itself should be the same as the name by which its
...
... host B will
not immediately send the message back to host A. The name each host
uses to identify itself should be the same as the name by which its
neighbors ...
...
A host adds its own name to the front of a path when it receives a
message from another host. Thus, if a message with path "A!X!Y!Z"
...
... A host adds its own name to the front of a path when it receives a
message from another host. Thus, if a message with path "A!X!Y!Z"
is passed from host A to host ...
... message from another host. Thus, if a message with path "A!X!Y!Z"
is passed from host A to host B, B will add its own name to the path
when it receives the message from A, e.g., "B!A!X!Y!Z". If B then
...
... host. Thus, if a message with path "A!X!Y!Z"
is passed from host A to host B, B will add its own name to the path
when it receives the message from A, e.g., "B!A!X!Y!Z". If B then
passes the message on to C, the message sent to C will contain the
...
... Reply-To" lines are in Internet format, and since many USENET hosts
do not yet have mailers capable of understanding Internet format, it
...
... requirement to fix this problem is placed on
implementations. However, the existing convention of placing the
host name and an "!" at the front of the path, and of starting the
path with the host name ...
... host name and an "!" at the front of the path, and of starting the
path with the host name, an "!", and the user name, should be
maintained when possible.
...
... submitting the message to the network. It should be verified by the
software at the submitting host.
...
... gateway program enters a mail message into the network at host
unix.SRI.COM, the lines might read:
...
... example, a message announcing an upcoming seminar could have an
expiration date the day after the seminar, since the message is not
useful after the seminar is over. Since local hosts have local
policies for expiration of news (depending on available disk space,
for instance), users are discouraged from providing expiration dates
...
... Control messages are used for communication among USENET
host machines, not to be read by users. Control messages are
distributed by the same newsgroup ...
... newsgroup mechanism as ordinary messages.
The body of the "Control" header line is the message to the host.
...
... increase it. A local newsgroup, such as nj.crazy-eddie, will
probably not be propagated by hosts outside New Jersey that do not
show such a newsgroup as valid ...
... sender belongs, or to which the machine belongs. The
intent of this line is to help identify the person posting the
message, since host names are often cryptic enough to make it hard
to recognize the organization by the electronic address.
...
...
This line contains the name of the host (with domains omitted) and a
white space separated list of colon-separated pairs of newsgroup ...
... newsgroup
news.groups, on host seismo. This information may be used by
certain user interfaces.
...
...
This message is part of the ihave/sendme protocol, which allows one
host (say A) to tell another host (B) that a particular message has
been received on A. Suppose that host ...
... This message is part of the ihave/sendme protocol, which allows one
host (say A) to tell another host (B) that a particular message has
been received on A. Suppose that host A receives message
...
... host (say A) to tell another host (B) that a particular message has
been received on A. Suppose that host A receives message
"<1234@ucbvax.Berkeley.edu>", and wishes to transmit the message to
host ...
... host A receives message
"<1234@ucbvax.Berkeley.edu>", and wishes to transmit the message to
host B.
...
... A sends the control message "ihave <1234@ucbvax.Berkeley.edu> A" to
host B (by posting it to newsgroup to.B). B responds with the
control message ...
...
This protocol can be used to cut down on redundant traffic between
hosts. It is optional and should be used only if the particular
situation makes it worthwhile. Frequently, the outcome is that,
since most original messages are short, and since there is a high
...
... newsgroup is removed from every host on the network, this command
should be used carefully by a responsible administrator ...
... The format of the file mailed back to the author should be the same
as that of the sys file. This format has one line per neighboring
host (plus one line for the local host), containing four colon
separated fields. The first field has the host name ...
... as that of the sys file. This format has one line per neighboring
host (plus one line for the local host), containing four colon
separated fields. The first field has the host name of the
...
... host (plus one line for the local host), containing four colon
separated fields. The first field has the host name of the
neighbor, the second field has a newsgroup ...
... of active newsgroups on the current host. The names of any obsolete
or new newsgroups are mailed to the user "usenet" and descriptions
...
... It is not a requirement that USENET hosts have mail systems capable
of understanding the Internet mail syntax, but it is strongly
...
... Internet syntax, replies will be difficult or impossible without an
Internet mailer. A host without an Internet mailer can attempt to
use the "Path" header ...
... use the "Path" header line for replies, but this field is not
guaranteed to be a working path for replies. In any event, any host
generating or forwarding news messages must have an Internet address
...
... generating or forwarding news messages must have an Internet address
that allows them to receive mail from hosts with Internet mailers,
and they must include their Internet address ...
... error messages caused by the mail transmission
would be sent to the originator of the news message, who has no
control over news transmission between two cooperating hosts
and does not know whom to contact. Transmission error messages
...
...
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 ...
...
Since news messages are usually short, and since a large number of
messages are often sent between two hosts in a day, it may make
sense to batch news messages. Several messages can be combined into
one large message, using conventions agreed upon in advance by the
...
... sense to batch news messages. Several messages can be combined into
one large message, using conventions agreed upon in advance by the
two hosts. One such batching scheme is described here; its use is
highly recommended.
...
...
The second argument (in this example rnews) determines which
batching scheme is being used. Cooperating hosts may use whatever
scheme is appropriate for them.
...
... USENET and the
algorithm followed by hosts in propagating news to the entire
logical network. Since all hosts ...
... hosts in propagating news to the entire
logical network. Since all hosts are affected by incorrectly
formatted messages and by propagation errors, it is important
for the method ...
... USENET is a directed graph. Each node in the graph is a host
computer, and each arc in the graph is a transmission path from
one host ...
... host
computer, and each arc in the graph is a transmission path from
one host to another host. Each arc is labeled with a newsgroup
...
... computer, and each arc in the graph is a transmission path from
one host to another host. Each arc is labeled with a newsgroup
pattern, specifying which newsgroup ...
... subnet. In
addition, the entire graph is (theoretically) connected. (In
practice, some political considerations have caused some hosts to be
unable to post messages reaching the rest of the network.)
...
... that are interested in at least one of the newsgroups of the
message. (Site A deems host B to be "interested" in a newsgroup if
the newsgroup ...
... the newsgroup matches the pattern on the arc from A to B. This
pattern is stored in a file on the A machine.) The hosts receiving
the incoming message examine it to make sure they really want the
...
... algorithm is the prevention of loops. The
above process would cause a message to loop along a cycle forever.
In particular, when host A sends a message to host B, host B will
...
... above process would cause a message to loop along a cycle forever.
In particular, when host A sends a message to host B, host B will
send it back to host ...
... In particular, when host A sends a message to host B, host B will
send it back to host A, which will send it to host ...
... host B, host B will
send it back to host A, which will send it to host B, and so on.
One solution to this is the history mechanism. Each host ...
... host B will
send it back to host A, which will send it to host B, and so on.
One solution to this is the history mechanism. Each host keeps
...
... host A, which will send it to host B, and so on.
One solution to this is the history mechanism. Each host keeps
track of all messages it has seen (by their Message-ID) and
...
... message is discarded immediately. This solution is sufficient to
prevent loops, but additional optimizations can be made to avoid
sending messages to hosts that will simply throw them away.
...
... in the "Path" line, the message is known to have passed through the
machine. Another optimization is that, if the message originated
on host A, then host A has already seen the message. Thus, if a
message is posted to newsgroup ...
... machine. Another optimization is that, if the message originated
on host A, then host A has already seen the message. Thus, if a
message is posted to newsgroup misc.misc, it will match the pattern
...
... newsgroup misc.misc, it will match the pattern
misc.all (where all is a metasymbol that matches any string), and
will be forwarded to all hosts that subscribe to misc.all (as
determined by what their neighbors ...
... subscribe to misc.all (as
determined by what their neighbors send them). These hosts make up
the misc subnetwork. A message posted to btl.general will reach all
...
... the misc subnetwork. A message posted to btl.general will reach all
hosts receiving btl.all, but will not reach hosts that do not get
...
... hosts receiving btl.all, but will not reach hosts that do not get
btl.all. In effect, the messages reaches the btl subnetwork. A
...
... messages posted to newsgroups misc.misc,btl.general will reach all
hosts subscribing to either of the two classes.
...