automod is a tool for doing fully automated, hands-off moderation of one or more USENET newsgroups. It provides facilities for reducing, if not altogether eliminating, unwanted crossposts, spam, and other "hit-and-run" commercial postings. As such, automod is perfect for moderating free-wheeling newsgroups whose members are wary of censorship and the potential for misuse that human moderation brings, but would like some relief from spam and the cultural clashes that can erupt through inappropriate crossposting.

What automod does not provide is content-based censorship. This means it is not suitable for moderating groups whose biggest problem is "staying on topic" and are therefore looking for content-based moderation. Read on, though, because you may discover that the reason your group is not staying on topic is because of hit-and-run posters and excessive crossposting. If that's the case, then you don't really need content-based moderation and automod may be able to help.

How It Works

automod keeps a database of approved posters for the newsgroup that it is moderating. Whenever someone new tries to post to the group, automod will check their email address against the database. If their address is not found, then automod will return their article to them along with a welcome message explaining the purpose of the group. The welcome message will also contain a special keyword and instructions on how to resubmit their article so that it will be posted to the group. All the new poster need do is reply to the message in which their article was returned, appending the special keyword to the end of their Subject line. When automod sees the keyword, it will put the new poster into the database of approved posters and from then on the poster will be able to post to the group freely, without needing the keyword any more.

Note that no one is barred or blacklisted from posting to the group. Anyone and everyone may join in and post freely, without censorship.

At first glance it may seem that this somewhat complex keyword process is achieving nothing, but take a closer look. First of all, it requires that the poster respond to the message which automod sent them. Most spammers use one-time throwaway email addresses, or illegal email addresses which go nowhere. In both cases, the spammers will never get automod's response so they won't learn the keyword and will never make it into the database of approved posters. So their spam will never be posted to the group. Even those spammers who do have valid, long-term email addresses rarely read the responses that they get (because they get a lot, mostly abusive) and if any should happen to read the response and learn the keyword, they are still unlikely to bother replying: their business is in automated mass postings and they haven't the time to give individual groups special attention. So automod has the potential to drastically reduce the amount of spam and non-targetted commercial postings that a group receives. In some groups it has eliminated it altogether.

A second important factor is that the new poster must read the welcome message to learn the keyword. Although the welcome message should not be a long-winded, full-blown FAQ for the group, it can outline what the group is for and any basic rules or conventions that it observes. This helps to reduce the "clueless newbie" factor, wherein a new poster wanders into the group without first reading its FAQ, and inadvertently annoys the group's existing members just through simple ignorance of the local culture. With automod's welcome message before them, new posters can decide whether the group is really the right place for them without accidentally starting a flame war in the process.

Another useful feature of automod is its ability to limit crossposting, through the use of white- or black-lists. Every newsgroup has its own culture, its own way of doing things, and often a body of shared beliefs held by most of its members. As such, when two very different newsgroups come into contact, there is the same potential for unproductive conflict as if a group of Harley owners were to drive through a tea party. To help avoid these pointless conflicts, automod lets you limit the groups to which articles may be crossposted. If you choose to use a black-list, then any articles which are crossposted to groups on the black-list will be rejected by automod and returned to the poster. If you choose to use a white-list, then any articles which are crossposted to groups not on the white-list will be similarly rejected and returned to the poster. Note that if someone believes strongly enough that their message really is appropriate for both groups, they are always free to post the same article, by hand, to each group individually. But at least the rest of the group is not forced to wade through the subsequent carnage.

For those newsgroups which are reasonably well behaved but have a couple of persistent trouble-makers, automod provides a watchList. Any poster whose address is placed on the watchList will have his post forwarded to one or more moderators for approval. In this way the moderators need only deal with the problem posters and the rest can post freely.

Once set up for a group, automod is remarkably maintenance free. We have automod running on the one group that I moderate. There is one other moderator and between the two of us we spend less than half an hour each week handling moderation of the group. Most of that is just answering questions from people who are having problems with their local newsfeeds and need help in tracking it down.

automod is available in source form as a tarred and gzipped file. It has been successfully tested on Linux 2.x, NetBSD 1.5.4 and SunOS 4.1.4, but should work on most other flavours of Unix as well.


automod is written by Dean Edmonds (, based on a prototype written by David Parsons.


automod-3.2.tgz (107K) Source code, tarred and gzipped.
automod-3.0.tgz (102K) Source code, tarred and gzipped.

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