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16. News transport gotcha's

16. News transport gotcha's

There are a few quirks in the network news transport software that you might encounter, and should be aware of. What follows is far from a complete list but does include the ones most commonly encountered.

16.1. Line lengths

The NNTP reference implementation package in use on the Internet has a limit on the number of characters that an individual line may contain. Submissions containing lines longer than 512 bytes will be corrupted because the reference servers will truncate the lines longer than 512 bytes.

In general you should limit your individual line lengths to 79 characters or less if possible. Systems that have fixed record lengths, such as some BITNET IBM servers, can drop text longer than that.

16.2. Old C News blanks-in-ng bug

If there is a newsgroup line in an article like this

Newsgroups: comp.unmoderated, comp.moderated

some older versions of C News fail to skip the space after the comma and so only see the group “comp.moderated” which of course is not moderated and passes it along. When the message hits a B News site, the space is squeezed out, the moderated group is seen for the first time and the message gets mailed in. This has been fixed in later C News releases, but sites running older software will still act this way.

16.3. B News non-local unapproved articles bug

As mentioned in Section 5, most news servers will automatically forward unapproved postings to the moderator. This should only occur for local postings, otherwise, situations can occur where the moderator gets far more than one copy of the same article. B News forwards non-local articles too. This coupled with the old C News blanks-in-ng bug has been responsible for moderators being deluged with hundreds of copies of an article. It's particularly nasty when the newsgroup has been recently unmoderated and not every server has respected the control message and the ex-moderator gets bombed.

To be fair, the B News behavior of mailing unapproved non-local articles to the moderator was not a “bug”. It was a “feature”.

It used to be that B News was the only game in town. It used to be that people ran ancient software versions forever. In such an environment, it was useful for a site receiving an article that should have gone to the moderator to assume that the previous hosts were running old software, and do the moderator-send itself. That is not the case today.

This bug has not been fixed, and never will be because B News is no longer being supported. Fortunately, B News is dying out.

16.4. Article size concerns

In some places, such as small systems and news-to-mail gateways, there are problems when individual article sizes exceed software limits. We need to either remove builtin system limitations or work around them. Since it takes time to remove old software versions and overcome hardware limitations netwide, the best course of action is to work around the limitations so that the news will get to all sites.

Individual postings should be less than or equal to 60K. If it is necessary to split the posting into multiple parts, each part should be less than or equal to 60K. This is due to the architecture restrictions of some older systems. This restriction is more in the minds of the users on the net than the software running it. Postings of 90K successfully make it through most present day news systems. Many mail systems have limitations of 100K on messages that pass through them. This is a concern because there are news to mail gateways that deliver and post news via electronic mail.

Note that some commercial gateways to the Internet have broken news and mail software that truncate anything over around 25K. Most are in the process of correcting their sub-standard software but at this point that has not been universally accomplished.

16.5. Amount of messages posted daily

Moderators of high volume newsgroups should try to limit the amount of data posted per day so as not to flood news spool directories on smaller systems. A good rule of thumb is to limit posting to 800K per day if possible.

If you are overwhelmed with posts on one day, it may be better to hold some articles back until the next day. Articles can be posted either in chronological order, or grouped by subject. On the other hand, it is not a good idea to loosen your acceptance standards simply because fewer articles were submitted in a given time period - in most cases it is better to have lower volume than lower quality.

16.6. Cross-posting to other moderated groups

None of the NetNews software handles cross-posted moderation very well, largely because there is no consensus on what the correct action is. What actually happens is that the posting software picks one of the moderated groups more or less at random (usually the first moderated group) and mails the message to its moderator. If the posting software used by the moderator who received the article does not check for other moderated newsgroups, the article will appear in the newsgroup of the other moderated group without being approved by the appropriate moderator.

Moderators should try to bullet-proof the posting software by making it check cross-posting to multiple moderated groups. But until NetNews gets a far more sophisticated posting scheme, e.g., one that lets a moderator add a new newsgroup to a message already in circulation, glitches like this will happen.

Remember that it is often VERY desirable to cross-post among moderated newsgroups:

  • comp.sources.misc “list of sources” also goes to comp.archives
    comp.sources.misc “intro posting” also goes to news.answers

Many of the postings in news.answers are cross-posted into the group from other moderated groups.

16.7. Extra headers on directly posted articles

Some submissions will arrive with two sets of headers. The “real” headers will be a set of generic mail headers; the news headers will be included as text within the body of the mail message. Even worse, in these cases the mail headers may indicate that the article is “From” usenet@site or news@site, making it difficult to identify or respond to the actual author.

This is the article-headers-in-body problem caused by C News feeding the article into UCB Mail or mailx instead of /bin/mail, which usually incorporates the news headers into the mail header.

Explanation: in C News, the newsbin/relay/injnews script is used by inews to do site-specific header bashing. When it discovers the newsgroup is moderated, it invokes mail to send off the article to the moderator (via mailpaths). Unlike B News and INN, where time has been spent to configure how to use the mail transport directly (to merge the news headers in with the mail headers), C News blindly punts the article into “mail” which is a user agent, which often refuses to accept “header-like” stuff at the beginning of a message as part of the RFC 822 header block. In essence, mail will often implicitly put a blank line at the beginning of the message, so the headers carefully crafted by injnews end up as part of the body instead of the mail headers.

If this becomes a problem for you, it would be appropriate to send a message to usenet@ and/or postmaster@ at the offending site with a suggestion on how to fix their C News injnews script.

[See Appendix B for a description of the solution. A template message is included that will allow you to inform the offending site of both the problem and the solution.]

16.8. Multiple copies of the same submission received

There are a number of different reasons why you may get many copies of a submission:

  • A mailer or gateway bug that keeps resending the same message (distinguished by having the same sites in “Received by” headers).
  • The posting site doesn't have the group marked as moderated (usually you only get a few extra copies of the message, all with short “Path” headers, if any).
  • Interaction with the C-news problem when there is a space in the list of newsgroups; when it gets to a B-news site, the space is squashed out and the moderated group is recognized (there are multiple newsgroups in the header, and your moderated group is not the first in the list).
  • Submitter was unaware that the group was moderated and repeatedly attempted to post the article to the group since their article did not immediately appear in their local newsgroup.

Contacting the administrator of the site where the problem posting was generated is probably a good first step.

16.9. B News static Newsgroup: header limit

B News inews has a static limit of 256 bytes for header lines. One might think that this limits Newsgroups: headers to about 254 bytes, but unfortunately the practical limit is lower than that. The Xref: header, which is generated from the Newsgroups: line plus article numbers, is longer than the Newsgroups: header. If the Xref: header at a particular site is longer than 256 bytes, the article simply will not appear at that site.

Since the length of the same article's Xref: header varies from site to site, and cannot be easily computed in advance, it is necessary to leave some spare room in the Newsgroups: header. Set a fair limit on the size of the Newsgroups: header, and make a policy prohibiting cross-posting to more groups than will fit on the line. Some moderators have decided on a 200-character limit for the entire Newsgroups: line.

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